# What will be the Sum? If

If the simple interest on a certain sum of money for 15 months at 7.5% p.a. exceeds the simple interest on the same sum for 8 months at 12.5% p.a. by Rs 32.50. The sum is :

- Rs 312
- Rs 312.50
- Rs 3120
- Rs 3120.50

**Answer: (3) Rs.3120**

**Explanation:-**

Let the sum be Rs.X.

According to the question,

X x 15 x 15 /12 x 2 x 100 – X x 8 x 25/2 x 12 x 100 = 32.50

X x 5 x 3 / 4 x 2 x 20 – X x 2 x 1 / 2 x 3 x 4 = 32.50

3 X / 32 – X / 12 = 32.50

(3 x 3 X – 8 X )/96 = 32.50

9 X – 8 X = 32.50 x 96

X = 3120

Then, the sum is Rs.3120

Hence, the answer is (3)Rs.3120