Question

Milinda takes $8\frac{1}{3}$ hours more when she works alone in comparison of when she works with Bill. While Bill takes $5\frac{1}{3}$ hours more when he work alone in comparison to the time, when he works with Milinda. How long it will take Bill to complete the work alone?

• A. 10 hours
• B. 15 hours
• C. 18 hours
• D. 12 hours

Answer 1

The correct option is D 12 hours

Consider option (d)
Time taken by Bill = 12 hours
Efficiency of Bill = 8.33%
Therefore, time taken by Bill and Milinda working together $=6\frac{2}{3}hours$
Hence, the efficiency of Milinda and Bill = 15%
Therefore efficiency of Milinda = 15 - 8.33 = 6.66%
Thus, the number of days taken by Milinda = 15, which is $8\frac{1}{3}$ days more than when both work together.
Hence, all the conditions satisfied.
$\begin{array}{ccccc}& & M& B+M& B\\ Efficiency& \to & 6.66\%& 15\%& 8.33\%\\ Numberofday& \to & 15& 6\frac{2}{3}& 12\end{array}$