
By: rctw1989 (offline) Friday, March 01 2013 @ 07:15 AM CST (Read 742 times)



rctw1989 
Need some help for the following qn (model or algebra approach is ok)
8 yrs ago the ratio of x's age to Y's age was 8:1. Now the ratio is 10:3. How old will y be in 6 yrs' time. tks (answer is 18 yrs old)

Newbie
Registered: 12/31/12 Posts: 3





By: echeewh (offline) Friday, March 01 2013 @ 03:32 PM CST



echeewh 
Hi there,
Following pls find my worked solution:
<8 years ago>
X : Y
8 : 1
<now>
X : Y
10 : 3
Since age difference between X and Y are constant (7 units in both instances), then we have ...
for Y,
3u  1u > 8 yrs
2u > 8 yrs
1u > 4 yrs
Hence, now Y's age is 3u > 3 × 4 = 12 yrs
In 6 years time, Y's age is (12 + 6) = 18 yrs old
==================
Trust this helps.
Do let me know again if there's further clarification.
Cheers,
Edward

Active Member
Registered: 04/21/11 Posts: 627





By: rctw1989 (offline) Saturday, March 02 2013 @ 04:50 AM CST



rctw1989 
hi edward
tks for your help. just today i used guess n check to solve it (multiplying the 2 respective ratios by 2, 3,4 ...
8 yrs ago now
8:1 10:3
16:2 20:6
24:3 30:9
32:4 40:12 ( check 32 +8 =40, and 4+8 =12, bingo) ans 12+6=18
wondering if there is a third way to solve, using model?
have a great weekend

Newbie
Registered: 12/31/12 Posts: 3



