Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?
A. 4
B. 6
C. 8
D. 10
E. 12
D. 10 days.
Krishna – Could you please explain the answer. I’m not getting it with the info given in the question.
Thanks
Milind
Milind,
I found that my answer is incorrect. Correct answer is 12. E.
Two machines take 3 days to produce 5/4W widgets. which means they take 12/5 days to produce W widgets.
The questions gives use that x = y+2 (consider x and y as number of hours for machines X and Y to produce W widgets.)
now 1/x + 1/y = 5/12 (i guess you know this formula for combining job works) after solving you get y as 4.(i did my prev calc incorrectly and ended up with y value 3). x=y+2 = 6. to produce W widgets. So, to produce twice the amount ’2w’ widgets it will take twice the time, which is 12 days.
The questions tricks us by saying ‘w’ widgets. Consider producing ‘W’ widgets as a job(like in most other questions).
Thanks Krishna.
Actually after getting this equation:
=>5y^2 – 14y -24 = 0
I was only thinking of the factors -20 and 6 and was thinking that if y=20, then x=22 but didn’t realize that y^2 has a quotient too which will reduce these 2 factors and then I and way trying to solve it verbally……
Thanks
E
Eqn: 5X^2-14x-24=0
X=4
For X: w is produced in 6 days
2w in 12 days
E. i love dis question.
@krishna:
i am clear with the solution thanks.
but should it be x+2=y??
as x takes 2 days more to produce an amnt that is equal to y?? pls clarify