Question

Jaidev 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?

Answer 1

As per the question

The time taken by jaidev to walk across the school ground $=2\frac{1}{5}$ minutes $=\frac{11}{5}$ minutes

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

The LCM of $5$ and $4$ is $20.$

$\therefore \frac{11}{5}=\frac{11\times 4}{5\times 4}=\frac{44}{20}$ and $\frac{7}{4}=\frac{7\times 5}{4\times 5}=\frac{35}{20}$.

Now, $\frac{35}{20}<\frac{44}{20}$.

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

$\Rightarrow$ Rahul takes less time.

The difference between the time taken by Jaidev and Rahul to walk across the school ground $=\frac{11}{5}-\frac{7}{4}=\frac{11\times 4-7\times 5}{20}$

[$\because$ L.C.M. of $5$ and $4$ is $20$ ]

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

Thus, Rahul takes $\frac{9}{20}$ minutes less than Jaidev to walk across the school ground.