if 3 taps are opened together a tank is filled in 3 hrs . one of the taps alone can fill it in 10 hrs . and another in 15 hrs . in how many hours will the third tap fill it ?
part filled by three taps together in 1 hr = 1 / 3 part filled by one of the tap in 1 hr = 1 / 10 part filled by another tap in 1 hr = 1 / 15 part filled by third tap in 1 hr = 1 / 3 - ( 1 / 0 + 1 / 15 ) = 5 / 30 therefore the third tap can fill the whole tank in : 30 / 5 hrs . = 6 hrs . answer : d
divide(multiply(10, 3), subtract(10, add(divide(multiply(10, 3), 15), 3)))