A man riding on a bicycle at a speed of 21 km/h crosses a bridge in 6 minutes. Find the length of the bridge?

Given:

Speed of the man (S) = 21 km/h

Time taken to cross the bridge (T) = 6 minutes

Formula used:

Distance (D) = Speed (S) × Time (T)

Calculation:

Convert time from minutes to hours:

6 minutes = 6/60 hours = 0.1 hours

Distance (D) = 21 km/h × 0.1 hours

⇒ D = 2.1 km

∴ The correct answer is option 1.