A sum of money at simple interest amounts to Rs 815 in 3 years and to Rs 854 in 4 years. The sum is:

Rs 698

A sum of money at simple interest amounts to Rs 815 in 3 years and to Rs 854 in 4 years.

Simple interest of one year = difference between simple interest 4th year and 3rd year = 854 - 815 = 39

Simple interest of 3 years = 39 x 3 = 117

Thus, principal amount = 815 - 117 = 698