Mary and John can do a piece of work in 24 day; John and Vino in 30 days;Vino and Mary in 40 days. If Mary, John and Vino work together they will complete work in ?  Choose the correct choice from the following:	A) 77	B) 20	C) 27	D) 19	E) 17
Explanation:   Given that   Mary and John take 24 days; i.e., (Mary + John)'s 1 day's work = 124124   John and Vino take 30 days; i.e., (John + Vino)'s 1 day's work = 130130   Vino and Mary take 40 days; i.e., (Vino + Mary)'s 1 day's work = 140140   Adding above 3 equations, we get,   [(Mary + John) + (John + Vino) + (John + Vino)]'s 1 day's work = 124+130+140124+130+140   2((Mary + John + Vino)'s 1 days work = 124+130+140124+130+140   2(Mary + John + Vino)'s 1 days work = 5+4+31205+4+3120 = 110110   Therefore, (Mary + John + Vino)'s 1 days work = 120120   i.e., Mary, John and Vino together can complete the work in 20 days.   Answer: 20
<result>B</result>
Mary and John can do a piece of work in 24 day; John and Vino in 30 days;Vino and Mary in 40 days. If Mary, John and Vino work together they will complete work in ?