Question

a girl walk 12 km/h at a speed of 3 km/h what change should she make in her speed to take (1) an hour less and (2) an hour more to cover the distance

Answer 1

what should I do explanation

Answer 2

Answer:

(i) 1km/h

ii) 0.6km/h

Step-by-step explanation:

Time taken by the girl to walk 12km at a speed of 3km/h is distance/speed = 12/3 km/h = 4km/h

(i) Time should be less than 1 hour

distance/time = 12/3 km/h = 4km/h

So, the speed has to be increased by 1 km/h.

(ii) If the girl takes 1 hour more , than the time taken by the girl is 5h.

Therefore, the speed of the girl = distance/time

= 12 /5 km/h

= 2.4 km/h

Hence if the time is increased by 1 hr then the speed has to be decreased by 0.6 km/h.

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