Score Plus Forum Sign in
Log In / Sign Up
Home arrow Forums
Score Plus Forums
Welcome, Guest
Please Login or Register.    Lost Password?
Score Plus Forums International Education GRE Free GRE Practice Material GRE Math
Know the answer but need an explaination (0 viewing) 
Go to bottom Post Reply Favoured: 0
TOPIC: Know the answer but need an explaination
#2663
GRE_Savvy (User)
Fresh Boarder
Posts: 1
graphgraph
User Offline Click here to see the profile of this user
Know the answer but need an explaination 1 Year ago Karma: 0  
Can somebody help me with this?

Question
If the ratio of the ages of two friends A and B is in the ratio 3 : 5 and that of B and C is 3 : 5 and the sum of their ages is 147, then how old is B?

1. 15 years
2. 75 years
3. 49 years
4. 45 years
5. 27 years


The answer is 45 years, but what is the correct approach to solve it?
 
Report to moderator   Logged Logged  
  The administrator has disabled public write access.
#2682
Huzefa (Moderator)
Moderator
Posts: 1017
graphgraph
User Offline Click here to see the profile of this user
Re:Know the answer but need an explaination 1 Year ago Karma: 13  
GRE_Savvy wrote:
Can somebody help me with this?

Question
If the ratio of the ages of two friends A and B is in the ratio 3 : 5 and that of B and C is 3 : 5 and the sum of their ages is 147, then how old is B?

1. 15 years
2. 75 years
3. 49 years
4. 45 years
5. 27 years


The answer is 45 years, but what is the correct approach to solve it?

Hello GRESavvy..

This problem can be dealt with in the following easy way:

Since A:B IS 3:5, then A = 3/5 B and since B:C = 3:5, then C = 5/3 B.

Now the sum of all three is 147. Hence we have A + B + C = 147. Substituing for A and C in this we get 3/5 B + B + 5/3 B = 147

Multiply throughout by 15 and solve to get B = 45

Keep Posting
 
Report to moderator   Logged Logged  
  The administrator has disabled public write access.
#3739
madhwani_vicky (User)
Senior Boarder
Posts: 78
graphgraph
User Offline Click here to see the profile of this user
Re:Know the answer but need an explaination 10 Months ago Karma: 0  
GRE_Savvy wrote:
Can somebody help me with this?

Question
If the ratio of the ages of two friends A and B is in the ratio 3 : 5 and that of B and C is 3 : 5 and the sum of their ages is 147, then how old is B?

1. 15 years
2. 75 years
3. 49 years
4. 45 years
5. 27 years


The answer is 45 years, but what is the correct approach to solve it?


One more method:

since A:B = 3:5 and B:C = 3:5

Hence, A:B:C = 9:15:25

therefore, let A=9x, B=15x, C=25x

A+B+C = 9x + 15x + 25x
= 49x

49x = 147 (given)
x = 3

The age of B we assumed 15x
hence, B's age =15 *3 = 45 yrs
 
Report to moderator   Logged Logged  
 
Last Edit: 2009/09/30 09:46 By madhwani_vicky.
  The administrator has disabled public write access.
Go to top Post Reply
Powered by FireBoardget the latest posts directly to your desktop