Q313
To do a certain work, the ratio of the efficiencies of X and Y is 5 : 4. Working together, they can complete the same work in 10 days. Y alone starts the work and leaves after 5 days. The remaining work will be completed by X alone in:
A.
14 days
AnswerB.
12 days
C.
15 days
D.
10 days
Answer: Option A
Solution
Answer: Option A
Solution:
\begin{array}{*{20}{c}}
{}&{\text{X}}&{}&{\text{Y}} \\
{{\text{Efficiency}}}&5&:&4
\end{array}Total work = (5 + 4) × 10 = 90
Y × 5 + X × a = 90
4 × 5 + 5 × a = 90
20 + 5a = 90
5a = 70
a = 14