a is twice as good as b . and together they finish a piece of work in 18 days . in how many days will a alone finish the work
( a ' s 1 day work ) : ( b ' s 1 day work ) = 2 : 1 a + b 1 day work = 1 / 18 a ' s 1 day work = ( 1 / 18 ) * ( 2 / 3 ) = 1 / 27 a alone can finish the work in 27 days answer is b
inverse(multiply(divide(inverse(18), add(const_2, const_1)), const_2))