Last visit was: 26 Apr 2024, 06:09 It is currently 26 Apr 2024, 06:09

Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Kudos
avatar
Intern
Intern
Joined: 11 May 2013
Posts: 7
Own Kudos [?]: 80 [27]
Given Kudos: 0
Send PM
Director
Director
Joined: 17 Dec 2012
Posts: 589
Own Kudos [?]: 1519 [2]
Given Kudos: 20
Location: India
Send PM
avatar
SVP
SVP
Joined: 27 Dec 2012
Status:The Best Or Nothing
Posts: 1562
Own Kudos [?]: 7208 [3]
Given Kudos: 193
Location: India
Concentration: General Management, Technology
WE:Information Technology (Computer Software)
Send PM
GMAT Club Legend
GMAT Club Legend
Joined: 19 Dec 2014
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Posts: 21846
Own Kudos [?]: 11668 [2]
Given Kudos: 450
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
2
Kudos
Expert Reply
livfcind wrote:
EMPOWERgmatRichC wrote:
Hi All,

Everyone who posted in this thread seems comfortable with prime factorization, but for anyone coming across this post who isn't completely comfortable with the "math", here's how prime factorization "works" - every positive integer (except the number 1) is either a prime number OR the product of a bunch of prime numbers.

For example, 2 and 3 are both prime numbers, but 4 is the product of 2 and 2.

Here, we're given a BIG number and asked to figure out the numbers that make up its PRODUCT. Since the numbers 3 and 5 are prime and 4 = 2^2, this is a big "clue" that we can use prime factorization to get to the correct answer.

So, let's prime factor 216,000

You can break this number up any way you choose, but I usually look for a logical "split"...

(216)(1,000)

(216) =
(4)(54)
(4)(6)(9)
(4)(2)(3)(3)(3)

**NOTICE that we have one 4 and one 2**

(1,000)
(10)(10)(10)
(2)(5)(2)(5)(2)(5)

**NOTICE that we have three 2s***

We now have enough information to determine how many 3s, 4s and 5s make up 216,000:

Three 3s
Three 5s
We have one 4 and four 2s. The 2s can be "paired up" to create a 4, so we have
Three 4s

Final Answer:

GMAT assassins aren't born, they're made,
Rich

Hi,

How is number of lures 3? I got to 4^3, but this is what i thought :
64 = 4*16. Since each lure weights 4 grams, he sold 16 lures. How does 'No. of X' translate into a exponential and not a multiplication?


Hi livfcind,

With certain types of questions, you have to be very careful about what you are told vs. what you are ASKED to solve.

This prompt gives us the weights of 3 types of lures (3 grams, 4 grams and 5 grams, respectively) and we're told that there are a certain number of each type. The PRODUCT of the WEIGHTS of the individual lures is 216,000 grams. As a simpler example, if we had just ONE of EACH lure, the product would be....

(3)(4)(5) = 60 grams

We wouldn't do anything else with this information, since we could answer the question that was asked (re: "how many of the 4-gram lures were there?")

Based on your post, I think that you understand the prime-factorization involved - and that we can rewrite 216,000 as....

216,000 =
(3)(3)(3)(4)(4)(4)(5)(5)(5)

This means that we have three 3-gram lures, three 4-gram lures and three 5-gram lures. At this point, there's no more work to be done since we know how many of the medium lures (re: the 4-gram lures) were sold: three.

GMAT assassins aren't born, they're made,
Rich
avatar
Intern
Intern
Joined: 27 Sep 2012
Status:Determined..700 will be my Revenge
Posts: 8
Own Kudos [?]: 6 [1]
Given Kudos: 5
Location: United States
Send PM
Re: How many medium lures did Bill sell? [#permalink]
1
Kudos
The answer should be D.

Start with doing the Prime Factorization of the number 216000.

You will get (2)with exponent 6.

Which is nothing but 4 with exponent 3.

Thanks
avatar
Intern
Intern
Joined: 30 May 2012
Posts: 2
Own Kudos [?]: [0]
Given Kudos: 9
Send PM
Re: How many medium lures did Bill sell? [#permalink]
total weight = 216000

weight of medium lure - 4 gm
by factoring we get 5*5*5*3*3*3*4*4*4
THUS MEDIUM LURE = 3
GMAT Club Legend
GMAT Club Legend
Joined: 19 Dec 2014
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Posts: 21846
Own Kudos [?]: 11668 [0]
Given Kudos: 450
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
Expert Reply
Hi All,

Everyone who posted in this thread seems comfortable with prime factorization, but for anyone coming across this post who isn't completely comfortable with the "math", here's how prime factorization "works" - every positive integer (except the number 1) is either a prime number OR the product of a bunch of prime numbers.

For example, 2 and 3 are both prime numbers, but 4 is the product of 2 and 2.

Here, we're given a BIG number and asked to figure out the numbers that make up its PRODUCT. Since the numbers 3 and 5 are prime and 4 = 2^2, this is a big "clue" that we can use prime factorization to get to the correct answer.

So, let's prime factor 216,000

You can break this number up any way you choose, but I usually look for a logical "split"...

(216)(1,000)

(216) =
(4)(54)
(4)(6)(9)
(4)(2)(3)(3)(3)

**NOTICE that we have one 4 and one 2**

(1,000)
(10)(10)(10)
(2)(5)(2)(5)(2)(5)

**NOTICE that we have three 2s***

We now have enough information to determine how many 3s, 4s and 5s make up 216,000:

Three 3s
Three 5s
We have one 4 and four 2s. The 2s can be "paired up" to create a 4, so we have
Three 4s

Final Answer:

GMAT assassins aren't born, they're made,
Rich
User avatar
Senior Manager
Senior Manager
Joined: 07 Apr 2014
Status:Math is psycho-logical
Posts: 340
Own Kudos [?]: 386 [0]
Given Kudos: 169
Location: Netherlands
GMAT Date: 02-11-2015
WE:Psychology and Counseling (Other)
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
Just as an equation, using sort of the unknown mupltiplier approach:

(3^x)*(4^x)*(5^x)= 216.000. Here you need the prime factorization of 216.000, which I will not show as it has been shown above.

Then you get this:
(3^x)*(4^x)*(5^x) = (3^3)*(4*3)*(5^3), so 4^x = 4*3 and x=3.

Does this make any sense?
Board of Directors
Joined: 17 Jul 2014
Posts: 2163
Own Kudos [?]: 1180 [0]
Given Kudos: 236
Location: United States (IL)
Concentration: Finance, Economics
GMAT 1: 650 Q49 V30
GPA: 3.92
WE:General Management (Transportation)
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
jabronyo wrote:
Bill owns a large collection of fishing lures consisting of small, medium, and large lures that weigh 3, 4, and 5 grams each, respectively. If the product of the lure weights that Bill sold to his friend is 216,000 grams, how many medium lures did he sell?

A. 6
B. 5
C. 4
D. 3
E. 2



pretty straight forward question...find the prime factorization of 216,000 and tell the exponent number for 4 or 2^2.

first step:
216,000 = 216 * 1000
1000 = 10^3 or 5^3 * 2^3.
216 = 2 * 108 = 2*2* 54
54 = 2*27 = 2*3^3.
total, we have:
2^3(from 1000) * 5^3(from 1000) * 2^3(from 216) * 3^3(from 2016)
combine:
2^6 * 5^3 * 3^3
we can rewrite 2^6 as 4^3.
since we are asked for the exponent for 4, the answer should be 3 - D
VP
VP
Joined: 07 Dec 2014
Posts: 1072
Own Kudos [?]: 1561 [0]
Given Kudos: 27
Send PM
Bill owns a large collection of fishing lures consisting of [#permalink]
Bill owns a large collection of fishing lures consisting of small, medium, and large lures that weigh 3, 4, and 5 grams each, respectively. If the product of the lure weights that Bill sold to his friend is 216,000 grams, how many medium lures did he sell?

A. 6
B. 5
C. 4
D. 3
E. 2

the product of one set of three lures--s,m,l--will=3*4*5=60 grams
the product of three sets of three lures will=60^3=216,000 grams
in three sets there will be 3 medium lures
D
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 18761
Own Kudos [?]: 22055 [0]
Given Kudos: 283
Location: United States (CA)
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
Expert Reply
jabronyo wrote:
Bill owns a large collection of fishing lures consisting of small, medium, and large lures that weigh 3, 4, and 5 grams each, respectively. If the product of the lure weights that Bill sold to his friend is 216,000 grams, how many medium lures did he sell?

A. 6
B. 5
C. 4
D. 3
E. 2


We can break down 216,000 into primes:

216,000 = 216 x 1000 = 6^3 x 10^3 = 2^3 x 3^3 x 2^3 x 5^3 = 2^6 x 3^3 x 5^3

However, we really want to break the number 216,000 into factors of 3, 4, and 5 to match the weights of the lures that he sold. Thus, we should rewrite the product as:

216,000 = 2^6 x 3^3 x 5^3 = 4^3 x 3^3 x 5^3

Since each medium lure weighed 4 grams, he sold 3 medium lures.

Answer: D
Manager
Manager
Joined: 03 Aug 2019
Posts: 64
Own Kudos [?]: 64 [0]
Given Kudos: 171
Location: India
Concentration: Operations, Strategy
GPA: 4
WE:Operations (Aerospace and Defense)
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
EMPOWERgmatRichC wrote:
Hi All,

Everyone who posted in this thread seems comfortable with prime factorization, but for anyone coming across this post who isn't completely comfortable with the "math", here's how prime factorization "works" - every positive integer (except the number 1) is either a prime number OR the product of a bunch of prime numbers.

For example, 2 and 3 are both prime numbers, but 4 is the product of 2 and 2.

Here, we're given a BIG number and asked to figure out the numbers that make up its PRODUCT. Since the numbers 3 and 5 are prime and 4 = 2^2, this is a big "clue" that we can use prime factorization to get to the correct answer.

So, let's prime factor 216,000

You can break this number up any way you choose, but I usually look for a logical "split"...

(216)(1,000)

(216) =
(4)(54)
(4)(6)(9)
(4)(2)(3)(3)(3)

**NOTICE that we have one 4 and one 2**

(1,000)
(10)(10)(10)
(2)(5)(2)(5)(2)(5)

**NOTICE that we have three 2s***

We now have enough information to determine how many 3s, 4s and 5s make up 216,000:

Three 3s
Three 5s
We have one 4 and four 2s. The 2s can be "paired up" to create a 4, so we have
Three 4s

Final Answer:

GMAT assassins aren't born, they're made,
Rich

Hi,

How is number of lures 3? I got to 4^3, but this is what i thought :
64 = 4*16. Since each lure weights 4 grams, he sold 16 lures. How does 'No. of X' translate into a exponential and not a multiplication?
Manager
Manager
Joined: 03 Aug 2019
Posts: 64
Own Kudos [?]: 64 [0]
Given Kudos: 171
Location: India
Concentration: Operations, Strategy
GPA: 4
WE:Operations (Aerospace and Defense)
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
EMPOWERgmatRichC wrote:
livfcind wrote:
EMPOWERgmatRichC wrote:
Hi All,

Everyone who posted in this thread seems comfortable with prime factorization, but for anyone coming across this post who isn't completely comfortable with the "math", here's how prime factorization "works" - every positive integer (except the number 1) is either a prime number OR the product of a bunch of prime numbers.

For example, 2 and 3 are both prime numbers, but 4 is the product of 2 and 2.

Here, we're given a BIG number and asked to figure out the numbers that make up its PRODUCT. Since the numbers 3 and 5 are prime and 4 = 2^2, this is a big "clue" that we can use prime factorization to get to the correct answer.

So, let's prime factor 216,000

You can break this number up any way you choose, but I usually look for a logical "split"...

(216)(1,000)

(216) =
(4)(54)
(4)(6)(9)
(4)(2)(3)(3)(3)

**NOTICE that we have one 4 and one 2**

(1,000)
(10)(10)(10)
(2)(5)(2)(5)(2)(5)

**NOTICE that we have three 2s***

We now have enough information to determine how many 3s, 4s and 5s make up 216,000:

Three 3s
Three 5s
We have one 4 and four 2s. The 2s can be "paired up" to create a 4, so we have
Three 4s

Final Answer:

GMAT assassins aren't born, they're made,
Rich

Hi,

How is number of lures 3? I got to 4^3, but this is what i thought :
64 = 4*16. Since each lure weights 4 grams, he sold 16 lures. How does 'No. of X' translate into a exponential and not a multiplication?


Hi livfcind,

With certain types of questions, you have to be very careful about what you are told vs. what you are ASKED to solve.

This prompt gives us the weights of 3 types of lures (3 grams, 4 grams and 5 grams, respectively) and we're told that there are a certain number of each type. The PRODUCT of the WEIGHTS of the individual lures is 216,000 grams. As a simpler example, if we had just ONE of EACH lure, the product would be....

(3)(4)(5) = 60 grams

We wouldn't do anything else with this information, since we could answer the question that was asked (re: "how many of the 4-gram lures were there?")

Based on your post, I think that you understand the prime-factorization involved - and that we can rewrite 216,000 as....

216,000 =
(3)(3)(3)(4)(4)(4)(5)(5)(5)

This means that we have three 3-gram lures, three 4-gram lures and three 5-gram lures. At this point, there's no more work to be done since we know how many of the medium lures (re: the 4-gram lures) were sold: three.

GMAT assassins aren't born, they're made,
Rich


Thanks a lot for the clarification ! I missed the "multiplication" part. Mistakes like these are the reason why i'm still stuck on Q50 :(
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 32685
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: Bill owns a large collection of fishing lures consisting of [#permalink]
Moderators:
Math Expert
92933 posts
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne