The sum of two numbers is 520. If the bigger number is decreased by 4% and the smaller number is increased by 12% then the numbers obtained are equal. The smaller number is :

Answer: Option B

Let the bigger number is a and the smaller number is (520 - a)
According to the question,
a × $$\frac{(100-4)}{100}$$   = (520 - a) × $$\frac{(100+12)}{100}$$
$$\frac{96a}{100}$$ = (520 - a) $$\frac{112}{100}$$
96a = (520 - a) 112
13a = 3640
a = 280
Hence, bigger number = 280
Smaller number = (520 - 280) = 240