a man , a woman and a boy can together complete a piece of work in 3 days . if a woman alone can do it in 6 days and a boy alone in 18 days , how long will a man take to complete the work ?
"explanation : ( 1 man + 1 woman + 1 boy ) ’ s 1 day ’ s work = 1 / 3 1 wo man ’ s 1 day work = 1 / 6 1 boy ’ s 1 day ’ s work = 1 / 18 man alone can finish the work in 9 days . answer : option d"
inverse(subtract(inverse(3), add(inverse(6), inverse(18))))