20 binders can bind 1400 books in 21 days . how many binders will be required to bind 1600 books in 20 days ?
"binders books days 20 1400 21 x 1600 20 x / 20 = ( 1600 / 1400 ) * ( 21 / 20 ) = > x = 24 answer : a"
divide(divide(1600, 20), divide(1400, multiply(20, 21)))