GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

It is currently 30 May 2020, 11:12

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

How to find continued ratio in easiest way?

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

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
Joined: 04 Nov 2015
Posts: 6
How to find continued ratio in easiest way?  [#permalink]

Show Tags

New post 04 Nov 2015, 07:27
Could you please help me out to find the easiest way to find the continued ratio of following problems?

(1) Find A:B:C:D, if A:B= 4:5 , B:C= 2:3 , and B:D= 1:7


(2) Find the continued ratio of A, B, C, and D, if A:B= 20:27 , B:C= 8:15 and C:D= 5:6


please explain the easiest way
SVP
SVP
avatar
B
Joined: 06 Nov 2014
Posts: 1861
Re: How to find continued ratio in easiest way?  [#permalink]

Show Tags

New post 04 Nov 2015, 20:12
safeer wrote:
Could you please help me out to find the easiest way to find the continued ratio of following problems?

(1) Find A:B:C:D, if A:B= 4:5 , B:C= 2:3 , and B:D= 1:7


(2) Find the continued ratio of A, B, C, and D, if A:B= 20:27 , B:C= 8:15 and C:D= 5:6


please explain the easiest way


Hi safeer,

The best way to find out the continued ratio would be by making the denominator of the first and the numerator of the next term same
A/B = 4/5, (i)
B/C = 2/3, (ii)
B/D = 1/7 (iii)

If we make the denominator and numerator of (i) and (ii) same,

We have A/B = 8/10 and B/C = 10/15
Hence, we have A:B:C = 8:10:15

Now from (iii), we can write B/D = 1/ 7 = 10/70 (making the value of B equal)

Hence A:B:C:D = 8:10:15:70

The similar technique can be applied in the 2nd question too.
Let me know if you are facing difficulties in solving the problem.
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 10477
Location: Pune, India
Re: How to find continued ratio in easiest way?  [#permalink]

Show Tags

New post 05 Nov 2015, 19:46
safeer wrote:
Could you please help me out to find the easiest way to find the continued ratio of following problems?

(1) Find A:B:C:D, if A:B= 4:5 , B:C= 2:3 , and B:D= 1:7


(2) Find the continued ratio of A, B, C, and D, if A:B= 20:27 , B:C= 8:15 and C:D= 5:6


please explain the easiest way


Responding to a pm:

Conceptually, this is what you should understand:
Given two ratios
A:B = 4:5 -> this means for every 4 of A, we have 5 of B
B:C = 2:3 -> this means for every 2 of B, we have 3 of C

Now, we have B common in the two ratios so we can compare A and C. But for that, the B of both ratios should be equal. Note that when you multiply/divide a ratio by a number, the ratio does not change. 2:3 is the same as 4:6 and 6:9 and 20:30 etc.

So you multiply the first ratio by 2 and the second ratio by 5 to get
A:B = 8:10 -> for every 8 of A, we have 10 of B
B:C = 10:15 -> for every 10 of B, we have 15 of C
B takes the value of LCM of 5 and 2 i.e. 10 in both ratios. Now, A and C are comparable. For every 8 of A, we have 10 of B and for 10 of B, we have 15 of C. So for every 8 of A, we have 15 of C.

A:B:C = 8:10:15

Do the same for the remaining ratio too. B:D = 1:7
B is 10 in the ratio above so multiply this ratio by 10. You get B:D = 10:70. So for every 10 of B, you have 70 of D.

A:B:C:D = 8:10:15:70

2.
A:B= 20:27 , B:C= 8:15 and C:D= 5:6
The numbers here will be cumbersome.
Multiply first ratio by 8 and second by 27
A:B = 160:216
B:C = 216:405

Multiply the 3rd ratio by 81 to make C 405.
C:D = 405:486

Final ratio A:B:C:D = 160:216:405:486
_________________
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 >
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 10477
Location: Pune, India
Re: How to find continued ratio in easiest way?  [#permalink]

Show Tags

New post 05 Nov 2015, 19:59
safeer wrote:
(3) Find continued ratio. If A:B= 2/3 : 3/4 , B:C= 4/5 : 5/6 , C:D= 6/7 : 7/8

this way not works for above (3) problem. could you please solve it and explain it step by step?


Use the same method but convert the ratio into integers first for ease.

Multiply the first ratio by 12 - the LCM of 3 and 4 - to get rid of the denominators (it will not change the ratio).
A:B = (2/3) * 12 : (3/4) * 12 = 8:9

Multiply the second ratio by 30
B:C = 24:25

Multiply the third ratio by 56
C:D = 48:49

Now you have three simple ratios just like before. You can find A:B:C:D
_________________
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 >
SVP
SVP
avatar
B
Joined: 06 Nov 2014
Posts: 1861
Re: How to find continued ratio in easiest way?  [#permalink]

Show Tags

New post 05 Nov 2015, 20:51
1
Quote:
(3) Find continued ratio. If A:B= 2/3 : 3/4 , B:C= 4/5 : 5/6 , C:D= 6/7 : 7/8
this way not works for above (3) problem. could you please solve it and explain it step by step?


In this case, A, B, C and D have been given in the form of fractions, so first we need to convert the ratio of A:B etc. in a proper form

A:B is nothing but A/B

Hence A:B = 2/3: 3/4 = (2/3)/ (3/4) = 2/3 * 4/3 = 8/9
Similarly, B:C = (4/5)/(5/6) = 4/5 * 6/5 = 24/25
and C:D = (6/7) / (7/8) = 6/7 * 7/8 = 3/4

From here on, you can solve it simply using the way used in the first problem.

Does it help?
GMAT Club Bot
Re: How to find continued ratio in easiest way?   [#permalink] 05 Nov 2015, 20:51

How to find continued ratio in easiest way?

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





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