Question

Joseph starts from his house to his office on motorcycle daily at fixed time.If he covers this distance at 40km/ h,he is late by 11 minute.However ,if he covers this distance at50km/h,he is late by5minute only.Find the distance between his house and the office?

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Answer 1

Answer:

50km/h.

Step-by-step explanation:

Because he was last in 11minutes

Answer 2

Step-by-step explanation:

let his normal speed and distance between his house and office be x and d respectively

then

time taken at normal speed =d/x

when his speed is at 40 km/hr time taken for him to travel d distance =d/40

therefore

d/40 -d/x=11/60

d/x=d/40-11/60. eqn 1

when his speed is at 50km/hr time taken to cover x distance=d/50

again

d/50-d/x=5/60

d/x=d/50-5/60. eqn 2

by eqn 1 and 2 we have

d/40-11/60=d/50-5/60

d/40-d/50=11/60-5/60

5d-4d/200=11-5/60

d=6/60×200

d=20km

hence distance between house and office is 20km