a is twice as good a workman as b and they took 11 days together to do the work b alone can do it in .
"wc = 2 : 1 2 x + x = 1 / 11 x = 1 / 33 = > 33 days answer : e"
multiply(divide(multiply(11, add(const_2, const_1)), const_2), const_2)