Let the distance travelled by both Sanchit and Archit be \( D \).
The time taken by each is given by:
We are given that Sanchit takes 20 minutes longer than Archit:
\[ \frac{D}{10} - \frac{D}{12} = 20 \text{ minutes} \]
Since 20 minutes is \( \frac{1}{3} \) of an hour, we rewrite the equation:
\[ \frac{D}{10} - \frac{D}{12} = \frac{1}{3} \]
Find the LCM of 10 and 12, which is 60:
\[ \frac{6D}{60} - \frac{5D}{60} = \frac{1}{3} \]
\[ \frac{D}{60} = \frac{1}{3} \]
Multiplying both sides by 60:
\[ D = 20 \]
Thus, the distance travelled is 20 km (Option D).