mitaliisrani wrote:U and V can complete a job together in 30 hours, V and W can do it in 40 hours, and W and U can do it in 60 hours. In how many hours will W finish the work individually?
A) 90hrs
B) 120 hrs
C) 240 hrs
D) 180 hrs
E) None of these\
OA isC...can some 1 plz post approach
Another approach would be to plug in our own value for the job and then to plug in the answer choices, which represent the time for W to complete the job alone.
Job = 240.
Answer choice C:
Rate for W alone = work/time = 240/240 = 1/hr.
Rate for V+W together = work/time = 240/40 = 6/hr.
So rate for V alone = (V+W together) - (W alone) = 6-1 = 5/hr.
Rate for U+V together = work/time = 240/30 = 8/hr.
So rate for U alone = (U+V together) - (V alone) = 8-5 = 3/hr.
Rate for W+U together = work/time = 240/60 = 4/hr.
This works, because rate for W=1 and U=3, and 1+3 = 4/hr.
The correct answer is C.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at
[email protected].
Student Review #1
Student Review #2
Student Review #3
