a is half good a work man as b and together they finish a job in 26 days . in how many days working alone b finish the job ?
"wc = 1 : 2 2 x + x = 1 / 26 = > x = 1 / 78 2 x = 1 / 78 = > 39 days answer : d"
multiply(26, divide(const_3, const_2))