a sum of money at simple interest amounts to $ 980 in 3 years and to $ 1024 in 4 years . the sum is :
"b $ 848 s . i . for 1 year = $ ( 1024 - 980 ) = $ 44 . s . i . for 3 years = $ ( 44 x 3 ) = $ 132 . principal = $ ( 980 - 132 ) = $ 848 ."
subtract(980, divide(multiply(subtract(1024, 980), 3), 4))