a sum of money at simple interest amounts to rs . 815 in 3 years and to rs . 844 in 4 years . the sum is :
"s . i . for 1 year = rs . ( 844 - 815 ) = rs . 29 . s . i . for 3 years = rs . ( 29 x 3 ) = rs . 87 . principal = rs . ( 815 - 87 ) = rs . 728 . answer : option d"
subtract(815, divide(multiply(subtract(844, 815), 3), 4))