two pipes a and b can fill a tank in 20 and 30 minutes respectively . if both the pipes are used together , then how long will it take to fill the tank ?
"part filled by a in 1 min = 1 / 20 part filled by b in 1 min = 1 / 30 part filled by ( a + b ) in 1 min = ( 1 / 20 + 1 / 30 ) = 1 / 12 so both pipes can fill the tank in 12 minutes . answer : a"
add(multiply(20, const_100), multiply(multiply(subtract(const_1, multiply(add(divide(const_1, 20), divide(const_1, 30)), const_2)), 20), const_60))