A cyclist rides for 2 hours at 15 km/hr and then for 3 hours at 20 km/hr. What is the average speed (in km/hr) of the cyclist for the entire trip?

Correct option is A

Given:
Time for first part, t₁ = 2 hours
Speed for first part, s₁ = 15 km/hr
Time for second part, t₂ = 3 hours
Speed for second part, s₂ = 20 km/hr
Formula Used:
​$$\text{Average speed} = \frac{\text{Total distance}}{\text{Total time}}$$​​
Total distance = (s₁ × t₁) + (s₂ × t₂)
Total time = t₁ + t₂
Solution:
Distance for first part = 15 × 2 = 30 km
Distance for second part = 20 × 3 = 60 km
Total distance = 30 + 60 = 90 km
Total time = 2 + 3 = 5 hours
Average speed = $$\frac {90}{5}$$​ = 18 km/hr