Question

X and Y together can complete a work in 6 days. X alone can complete it in 10 days. If Y does the work only for half a day daily, then in how many days will X and Y together complete the work?

• A. 7 days
• B. 5.5 days
• C. 6 days
• D. 10 days
• E. 7.5 days

Answer 1

The correct option is E

7.5 days

Y's 1 day's work = $(\frac{1}{6}-\frac{1}{10})=\frac{2}{30}=\frac{1}{15}$

Now, (X + Y)'s 1 day's work = $(\frac{1}{10}+\frac{1}{30})=\frac{4}{30}=\frac{2}{15}$, [$\because$ Y works for half day only]

So, X and Y together will complete the work in 7.5 days.