a and b can do a piece of work in 6 days , b and c in 7 days , c and a in 8 days . how long will c take to do it ?
"2 c = 1 / 7 + 1 / 8 – 1 / 6 = 20 / 168 = 10 / 84 c = 5 / 84 = > 84 / 5 = 16.8 days the answer is d ."
divide(multiply(6, const_3), subtract(divide(add(divide(multiply(6, const_3), 8), add(divide(multiply(6, const_3), 6), divide(multiply(6, const_3), 7))), const_2), divide(multiply(6, const_3), 6)))