a sum of money at simple interest amounts to rs . 820 in 3 years and to rs . 854 in 4 years . the sum is :
"s . i . for 1 year = rs . ( 854 - 820 ) = rs . 34 . s . i . for 3 years = rs . ( 34 x 3 ) = rs . 102 . principal = rs . ( 820 - 102 ) = rs . 718 . answer : b"
subtract(820, divide(multiply(subtract(854, 820), 3), 4))