<PRE><B>Question 272191</B>
A is 1/4 as old as B.
A = {{{1/4}}}B
:
5 years later A will be 1/3 as old as B.
A + 5 = {{{1/3}}}(B+5)
replace A with {{{1/4}}}B
{{{1/4}}}B + 5 = {{{1/3}}}(B+5)
multiply by 12 to get rid of the fractions; results:
3B + 12(5) = 4(B+5)
:
3B + 60 = 4B + 20
:
60 - 20 = 4B - 3B
:
B = 40 yrs 
then
A = {{{1/4}}}*40
A = 10 yrs





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