Andrew will be half as old as Larry in 3 years. Andrew will also be on

let age of Andrew =x, Larry =y 7 J = Z
we have (X+3) =1/2 *(y+3) so we have 2X-y =-3 ---1
we have (X+5) =1/3 * (z+5) ; => 3x-z=-10 ---2
adding above 2 equation we get, x+y-z =-7 ----3
we have z =15+y
from equation 3 and 4 we get x=8

Hence answer is B
Thanks,

did using options ..
started with B and came out to be correct

Andrew today = 8 , so 3 years later = 11 , so Larry after 3 years = 22
So larry today = 19
Also andrw after 5 years = 13 , so jeromi after 5 years = 39
So jeromi today 34
difference betweeb larry and jeromi = 15 ... so my assumed value of andrew age is correct.
Answer B

MANHATTAN GMAT OFFICIAL SOLUTION:

Let A = Andrew s age now, let L = Larrys age now, and let J = Jerome s age now.

Andrew will be half as old as Larry in 3 years --> 2(A + 3) = (L + 3)
Andrew will also be one-third as old as Jerome in 5 years --> 3(A + 5) = J + 5
If Jerome is 15 years older than Larry --> J = L + 15

You ultimately need to find the value of A. If you replace J in the second equation with (L + 15), both the first and second equations will contain the variables A and L:

3(A + 5) = J + 5 --> 3(A + 5) = (L + 15) + 5

Simplify the first two equations:
2(A + 3) = (L + 3); 3(A + 5) = (L + 15) + 5
2A + 6 = L + 3; 3A + 15 = L + 20

If you subtract the first equation from the second equation, you can cancel out Z, which will allow you to solve for A:
3A + 15 = L + 20
-(2A + 6 = L + 3)
_____________
A + 9 = 17
A = 8

Answer: B.

We can create the equations:

A + 3 = (1/2)(L + 3)

2A + 6 = L + 3

2A + 3 = L

and

A + 5 = (1/3)(J + 5)

3A + 15 = J + 5

3A + 10 = J

and

J = L + 15

Substituting L + 15 for J in the equation 3A + 10 = J, we have:

3A + 10 = L + 15

3A - 5 = L

Substituting 3A - 5 for L in the equation 2A + 3 = L, we have:

2A + 3 = 3A - 5

8 = A

Answer: B

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