Correct Answer - Option 4 : 70 km
Given:
Rajesh covers 140 km in 15 hours to reach office from home.
The speed of bus is 14 km/hr.
The speed of cycle is 7 km/hr.
Formula Used:
Time = Distance/Speed
Calculation:
Rajesh covers 140 km in 15 hours to reach office from home.
The total time taken = 140/15 = 28/3 hours
Let the distance covered by bus be x.
The time taken by bus = x/14
The distance covered by cycle = 140 - x
The time taken by cycle = (140 - x)/7
The total time taken = x/14 + (140 - x)/7
⇒ x/14 + (140 - x)/7 = 15
⇒ x + 140 × 2 - 2x = 15 × 14
⇒ x = 280 - 210 = 70 km
The distance covered by cycle = 140 - 70 = 70 km
∴ The distance covered by cycle is 70 km.
