Question 1007748
 Eighteen years ago the ratio of As age to B s age was 8:13.
 Their present ratios are 5:7. What is the present age of A? 
:
let x = the multiplier
then
5x = A's present age
and
7x = B's present age
:
18 years ago:
{{{((5x-18))/((7x-18))}}} = {{{8/13}}}
cross multiply
13(5x-18) = 8(7x-18)
65x - 234 = 56x - 144
65x - 56x = -144 + 234
9x = 90
x = 90/9
x = 10 is the multiplier
then
A = 5(10)
A = 50 yrs old now
:
:
Confirm this solution, find B's age; 10*7 = 70yrs old
{{{((50-18))/((70-18))}}} = {{{32/52}}} = {{{8/13}}}