GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 20 Oct 2018, 03:49

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

It takes Jack 2 more hours than Tom to type 20 pages. If

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Intern
Intern
User avatar
B
Status: never give up on yourself
Joined: 14 Apr 2018
Posts: 5
WE: Corporate Finance (Accounting)
Re: It takes Jack 2 more hours than Tom to type 20 pages. If  [#permalink]

Show Tags

New post 20 Jun 2018, 04:53
VeritasPrepKarishma wrote:
Barkatis wrote:
It takes Jack 2 more hours than Tom to type 20 pages. If working together, Jack and Tom can type 25 pages in 3 hours, how long will it take Jack to type 40 pages?

5
6
8
10
12

Can anyone explain the method to work with such problems ? Cause I always get them wrong !
And if you know any similar questions, please share. Thanks :)


You can solve equations like the one given below using some logic. Even if you do not have options, you can still get your answer very easily. You don't really need to make a quadratic.

\(\frac{20}{t} + \frac{20}{(t+2)} = \frac{25}{3}\)

Look at the right hand side of the equation. The fraction is in the lowest form. So you looking for a 3 somewhere in the denominator. Also note that 25/3 is a little more than 8.
Can 't' be 3? No, because 20/3 + 20/5 is a little more than 10.
Can 't+2' be 3? No, because then t = 1 and the sum on the left hand side will be more than 20.
Can 't+2' be 6 instead? 20/4 + 20/6 = 25/3
So t must be 4 and t+2 must be 6.



can you please explain what is wrong with my method
rate of jack =1/x
rate of tom=1/x-2
working together they will take=1/x + 1/x-2 = 1/3
i am not getting the correct answer
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8397
Location: Pune, India
Re: It takes Jack 2 more hours than Tom to type 20 pages. If  [#permalink]

Show Tags

New post 20 Jun 2018, 05:35
Abhishekgmatfit wrote:
VeritasPrepKarishma wrote:
Barkatis wrote:
It takes Jack 2 more hours than Tom to type 20 pages. If working together, Jack and Tom can type 25 pages in 3 hours, how long will it take Jack to type 40 pages?

5
6
8
10
12

Can anyone explain the method to work with such problems ? Cause I always get them wrong !
And if you know any similar questions, please share. Thanks :)


You can solve equations like the one given below using some logic. Even if you do not have options, you can still get your answer very easily. You don't really need to make a quadratic.

\(\frac{20}{t} + \frac{20}{(t+2)} = \frac{25}{3}\)

Look at the right hand side of the equation. The fraction is in the lowest form. So you looking for a 3 somewhere in the denominator. Also note that 25/3 is a little more than 8.
Can 't' be 3? No, because 20/3 + 20/5 is a little more than 10.
Can 't+2' be 3? No, because then t = 1 and the sum on the left hand side will be more than 20.
Can 't+2' be 6 instead? 20/4 + 20/6 = 25/3
So t must be 4 and t+2 must be 6.



can you please explain what is wrong with my method
rate of jack =1/x
rate of tom=1/x-2
working together they will take=1/x + 1/x-2 = 1/3
i am not getting the correct answer


How does 1/x + 1/x-2 equal 1/3?

\(\frac{1}{x} + \frac{1}{(x-2)} = \frac{(2x - 2)}{x(x - 2)} = \frac{5}{12}\)

Note how you get 5/12 - The combined rate is 25 pages in 3 hrs. But initially our work done was 20 pages which would then be done in (4/5)*3 = 12/5 hrs. So combined rate is 5/12.

When you solve the above, you get x = 6.

So Jack types 20 pages in 6 hrs. He will type 40 pages in 12 hrs.
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

GMAT Club Bot
Re: It takes Jack 2 more hours than Tom to type 20 pages. If &nbs [#permalink] 20 Jun 2018, 05:35

Go to page   Previous    1   2   [ 22 posts ] 

Display posts from previous: Sort by

It takes Jack 2 more hours than Tom to type 20 pages. If

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.