Machine M, N, O working simultaneously Machine M can produce x units in 3/4 of the time it takes machine N to produce the same amount of units. Machine N can produce x units in 2/7 the time it takes machine O to produce that amount of units. If all three machines are working simultaneously, what fraction of the total output is produced by machine N?	Choose the correct choice from the following answers.
A) 1/2	B) 7/13	C) 4/13	D) 8/29	E) 6/33
Now ultimately the speed of every machine is given with respect to Mach O.   So lets assume the speed of O, say 12 hrs to make x units (assuming 6 because we can see we will need to divide by 3 and 4   Mach O makes x units in 12 hrs   So, Mach N = 2/7 of O = 2/7*12 = 24/7 hrs to make x units   and Mach M = 3/4 of N = 3/4*24/7 = 1/6hrs to make x units   No they are running simultaneously. Lets see how much each mach makes in 1 hr   Mach O = x/12 units   Mach N = 7/24 units   Mach M = x/6 units   In 1 hr, together they make - x/12+7/24+x/6 = 13/24   So what ratio of this has Mach N made?   (7/24) / (13/24) = 7/13   Ans:7/13=7/13
<result>B</result>
Machine M, N, O working simultaneously Machine M can produce x units in 3/4 of the time it takes machine N to produce the same amount of units. Machine N can produce x units in 2/7 the time it takes machine O to produce that amount of units. If all three machines are working simultaneously, what fraction of the total output is produced by machine N?