Sudhin cycled at 8.5 km/h for 4 hours, then took an auto and traveled at 20 km/h for 1.5 hours, and then walked at 4 km/h for y hours. If Sudhin's overall average speed for the entire journey was 10 km/h, what is the value of y?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 1.5.
We know that,
Total distance = Average speed × Total time
Total distance covered,
⇒ 8.5 × 4 + 20 × 1.5 + 4 × y
= 64 + 4y
Total time taken,
⇒ 4 + 1.5 + y
= 5.5 + y
As per the question,
⇒ = 10
⇒ 64 + 4y = 55 + 10y
⇒ 6y = 9
⇒ y = 1.5 hr