a and b together can do a work in 6 days . if a alone can do it in 10 days . in how many days can b alone do it ?
"1 / 6 – 1 / 10 = 1 / 15 = > 15 answer : b"
add(inverse(subtract(divide(const_1, 6), divide(const_1, 10))), divide(const_2, add(const_2, const_3)))