If the area of a rectangle is increased by 32% and its breadth is increased by 10%, what is the percent increase in its perimeter?

None of the above

Formulae of net effect:

x + y + \(\frac{xy }{100 }\)

10 + x + \(\frac{10x }{100 }\) = 32%

10 + 1.1x = 32%

1.1x = 22%

x = 20%

Therefore, 

If length = 10 and breadth = 10 then, perimeter i.e. 2(l+b) = 40 

After increase - length = 12 and breadth = 11 then, perimeter i.e. 2(l+b) = 46

Increase in perimeter = 6

Percentage increase in perimeter = \(\frac{6}{40 }\) x 100 = 15%