Question

Ravish takes $2\frac{1}{5}$ minutes to walk across the school ground. Rahul takes $\frac{7}{4}$ minutes to do same. Who takes less time and by what fraction?

• A. Ravish and, by$\frac{3}{10}$ minute
• B. Ravish and, by $\frac{9}{20}$ minute
• C. Rahul and, by $\frac{3}{10}$ minutes
• D. Rahul and, by $\frac{9}{20}$ minutes

Answer 1

The correct option is D Rahul and, by $\frac{9}{20}$ minutes

As per the question

Time taken by Ravish to walk across the school ground = 2$\frac{1}{5}$ minutes = $\frac{11}{5}$ minutes

Time taken by Rahul to walk across the school ground = $\frac{7}{4}$ minutes

The LCM of 5 and 4 is 20.

$\therefore \frac{11}{5}=\frac{11\times 4}{5\times 4}=\frac{55}{20}$ and $\frac{7}{4}=\frac{7\times 5}{4\times 4}=\frac{35}{20}$.

Now, $\frac{35}{20}<\frac{55}{20}$.

$\therefore \frac{7}{4}<\frac{11}{5}$

$\Rightarrow$ Rahul takes less time.

The difference between the time taken by Ravish and Rahul to walk across the school ground = $\frac{11}{5}-\frac{7}{4}=\frac{11\times 4-7\times 5}{5\times 4}$

= $\frac{44-35}{20}=\frac{9}{20}$ minutes

Thus, Rahul takes $\frac{9}{20}$ minutes less than Ravish.