Question

A cyclist left the village for a station which is 32 km away. On the way back his speed was 1 km/hour greater spending on his way back 8 minutes less than on the way from village to station. Find the speed of cyclist's during the trip from the village to the station.

Answer 1

15 km/hr

Explanation:

Distance = speed × time

32 = S × t

t = 32/S

32 = (S + 1) × (t - 8/60)

32 = (S + 1) × (32/S - 2/15)

32 × 15S = (S + 1)(32×15 - 2S)

480S = (S + 1)(480 - 2S)

480S = 480S + 480 - 2S² - 2S

2S² + 2S - 480 = 0

S² + S - 240 = 0

S² + 16S - 15S - 240 = 0

S(S + 16) - 15(S + 16) = 0

(S - 15)(S + 16) = 0

S = 15, -16(not possible)

S = 15 km/hr