a does 4 / 5 th of a work in 20 days . he then calls in b and they together finish the remaining work in 3 days . how long b alone would take to do the whole work ?
explanation : a can finish the whole work in 20 × 5 / 4 days = 25 days a and b together finish the whole work in 5 × 3 days = 15 days therefore , b can finish the whole work in 25 b / 25 + b = 15 25 b = 15 ( 25 + b ) = 375 + 15 b 10 b = 375 and b = 375 / 10 = 37 ½ days . answer : option c
inverse(subtract(inverse(multiply(3, 5)), inverse(multiply(divide(5, 4), 20))))