a is twice as fast as b . if b alone can do a piece of work in 30 days , in what time can a and b together complete the work ?
"option b explanation : a can do the work in 30 / 2 i . e . , 15 days . a and b ' s one day ' s work = 1 / 15 + 1 / 30 = ( 2 + 1 ) / 30 = 1 / 10 so a and b together can do the work in 10 days ."
inverse(add(divide(const_1, 30), multiply(divide(const_1, 30), const_2)))