
The ages of a & b are in the ratio 7:5. After 10 years the ratio of their ages will be 9:7.The present age of B = ?
let x = the multiplier
then
7x = A's present age
and
5x = B's present age
:
Adding 10 yrs to their age produces a ratio of 9:7, there
=
cross multiply
7(7x+10) = 9(5x+10)
49x + 70 = 45x + 90
49x  45x = 90  70
4x = 20
x = 20/4
x = 5 is the multiplier
:
Their present ages
A: 5(7) = 35 yrs
B: 5(5) = 25 yrs
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