2021 · Q44
A person rode one-third of a journey at 60 km/hr, one-third at 50 km/hr and the rest at 40 km/hr. Had the person ridden half of the journey at 60 km/hr and the rest at 40 km/hr, he would have taken 4 minutes longer to complete the journey. What distance did the person ride ?
Elementary MathematicsTime, Speed and Distance
- A180 km
- B210 km
- C240 km
- D300 km
Explanation
Let the distance be D km. The first schedule takes D(1/180 + 1/150 + 1/120) = 37D/1800 hr; the second takes D(1/120 + 1/80) = D/48 hr. Their difference is D(1/48 − 37/1800) = D/3600 hr, given as 4 minutes = 1/15 hr. Hence D = 3600/15 = 240 km, option (c).