Bunuel wrote:
Jason can stack two shelves in 3 hours and Maria can stack three shelves in 2 hours. How long will it take them together, working at a constant rate, to stack thirteen shelves?
A. 5 hours
B. 6 hours
C. 6.5 hours
D. 11 hours
E. 12 hours
Kudos for correct solution.
Jason stack one shelve = 3/2 hours
Maria stack one shelve = 2/3 hours
Working together they stack one shelve = \((\frac{2}{3} *\frac{3}{2})/(\frac{2}{3} +\frac{3}{2})\)
= \(\frac{6}{13}\) hours
Now to stack 13 shelves = \(\frac{6}{13}*13\) = 6 Hours
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