a works twice as fast as b . if b can complete a work in 18 days independently , the number of days in which a and b can together finish the work is :
"explanation : ratio of rates of working of a and b = 2 : 1 . so , ratio of times taken = 1 : 2 a ' s 1 day ' s work = 1 / 9 b ' s 1 day ' s work = 1 / 18 ( a + b ) ' s 1 day ' s work = ( 1 / 9 + 1 / 18 ) = 3 / 18 = 1 / 6 so , a and b together can finish the work in 6 days answer is b"
inverse(add(divide(const_1, 18), multiply(const_2, divide(const_1, 18))))