a is half good a work man as b and together they finish a job in 18 days . in how many days working alone b finish the job ?
"c 27 wc = 1 : 2 2 x + x = 1 / 18 = > x = 1 / 54 2 x = 1 / 27 = > 27 days"
multiply(18, divide(const_3, const_2))