Question

Sharma is 20% less efficient than Kelkar. If Kelkar can do a piece of work in 24 days, then the number of days required by Sharma to complete the same work alone.

• A. 20
• B. 30
• C. 28.8
• D. can't be determined

Answer 1

The correct option is B 30

The efficiency of Sharma is $\frac{1}{5}$ times less than Kelkar.
$\therefore$ Time taken by Sharma will be $\frac{1}{4}$ times more than that by Kelkar.
Hence, time taken by Sharma = (1 + $\frac{1}{4})\times 24=30days$


Alternate Approach:
$\begin{array}{ccc}& Sharma& Kelkar\\ Efficiency& 0.8x& x\\ Numberofday& k& 0.8k=24\\ \because & 0.8k=24\Rightarrow k=30& \end{array}$
Thus Sharma required 30 days, to complete the work, alone.