Navjot invested his salary of Rs 8600 in two parts. The first part earned simple interest at 15% per annum for 4 years, which equalled the interest on the second part invested at 20% for 3 years. Find the difference between the two parts.

The two parts are equal, so the difference is Rs 0.

Interest on part 1 = P1 x 15 x 4 / 100 = 0.60 P1.

Interest on part 2 = P2 x 20 x 3 / 100 = 0.60 P2.

These are set equal, so 0.60 P1 = 0.60 P2, giving P1 = P2.

Each part = 8600 / 2 = 4300, so the difference = 0.