Age Problem?

Question

Please provide your answer and explanation 

Q) Andrew will be half as old as Larry in 3 years. Andrew will also be one-third as old as Jerome in 5 years. if Jerome is 15 years older than Larry, how old is Andrew?.

I'm struggling with the age problem in general. Is there a good method to solve these problems?

sidbidus · Answer

Is Anderw  8  yrs old. If right, I'll give the explanation.

tinman1412 · Answer

Yes, Andrew is 8 years old

sidbidus · Answer

Ok.

Just write equations as u read the ques.

A+3 = 1/2(L+3)
=> 2A + 3 = L ----(1)

A + 5 = 1/3 (J+5)
=> 3A + 10 = J
Since J = L + 15

=> 3A - 5 = L ---(2)

Using (1) and (2)

 A = 8

GMATBLACKBELT · Answer

Best way to do these problems is to write out every date.

 Now || 3yrs from now || 5yrs from now
 A || A+3 || A+5
 J || J+3 || J+5
 L || L+3 || L+5

Now make the equations for the appropriate years.

Since Andrew will be half as old as jerome in 3 years. you can rewrite it like this: 2(A+3)=L+3

Next equation: rewrite it just like above. Make the two sides equal to each other.

3(A+5)=J+5

Final one 15+L=J (since J is 15yrs older, adding 15 to L will equal J). 

Now solve:
J=15+L--> 3(A+5)=J+5--> 3A+15=15+L+5 --> 3A-5=L

2(A+3)=L+3--> 2A+6=3A-5+3 -->2A+6=3A-2 ---> A=8

tinman1412 · Answer

Very helpful explantion. Thanks,

Age Problem?

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