Question

The age of a and b in ratio5:3 after 6 years their ratio will be 7:5 what is the present age of a

Answer 1

Given,
presently a:b = 5:3. So, a = 5b/3 (i)
after 6 years, a+6:b+6 = 7:5

So,
5(a+6) = 7(b+6)
5a + 30 = 7b + 42
5a - 7b = 12
5(5b)/3 - 7b = 12 (from i)
25b/3 - 7b = 12
25b - 21b = 36 (dividing 3 both side)
4b = 36
b = 9
Substituting, b=9 in (i),
a = 5(9)/3
a = 5(3)
a = 15

SO, PRESENT AGE OF a is 15years.