a can do a piece of work in 15 days and b in 20 days . they began the work together but 5 days before the completion of the work , a leaves . the work was completed in ?
"explanation : ( x â € “ 5 ) / 15 + x / 20 = 1 x = 11 3 / 7 days answer is d"
add(divide(subtract(const_1, add(multiply(5, divide(const_1, 15)), multiply(5, divide(const_1, 20)))), divide(const_1, 20)), 5)