Question

A cyclist covers the first three kilometers at an average speed of 8 km/h, the other two kilometers at 3 km/h and the last two kilometers at 2 km/h. What is the approximate average speed (in km/h) of the entire journey?
1. 3
2. 2.4
3. 3.43
4. 3.8

Answer 1

Correct Answer - Option 3 : 3.43

Given:

Speed of cyclist in first 3 km = 8 km/h

Speed of cyclist in next 2 km = 3 km/h

Speed of cyclist in last 2 km = 2 km/h

Formula used:

(i) Speed = Distance/Time

(ii) Average speed = (Total distance travelled)/(Total time taken)

Calculations:

Average speed = (3 + 2 + 2)/{(3/8) + (2/3) + (2/2)}

⇒ 7/{(9 + 16 + 24)/24}

⇒ 7/(49/24)

⇒ (7 × 24)/49

⇒ 3.43 km/h

∴ The approximate average speed of the entire journey is 3.43 km/h.