Question

If 3% of (a + b) = 7% of (ab) and 5% of (a – b) = 4% of (ab) then what percentage of b is a?

Answer 1

Given, 3% of (a + b) = 7% of (ab)

=> 3a + 3b = 7ab......................(i)

5% of (a - b) = 4% of (ab)

=> 5a - 5b = 4ab.....................(ii)

Now, 5 x equation(i) + 3 x equation(ii),

15a + 15b + 15a - 15b = 35ab + 12ab

=> 30a = 47ab

=> b =

Plug the value of b in equation(i),

3a + 3 x = 7a

=> 3a + =

=> - 3a =

=> =

=> a = =

Let x% of b = a

=>

=> x = = 204.35%

Hence, 204.35% of b is a.