Question

A car travelling with 5/7 of its usual speed covers 42 km in 1 hr 40 min 48 sec

Answer 1

42 km = 42,000 m

1 hour 40 min 48 sec = 6048 sec

Given: distance = 42,000 m

Given: time = 6048 sec

Since, speed = distance/time

Hence, speed = 42,000 m/6048 sec

= 2625 m / 378 sec*5/7

= 5 m/s (approx)

Therefore, the car was traveling with a speed of 5 m/s.

Hope it helps.

Answer 2

Let's,the usual speed of car be x m/s.

Distance covered=42km

Time taken=(3600+2400+48)s

=6048seconds

Speed of car=d/t

=42000/6048 m/s

=6.94 m/s

usual speed,u * 5/7 =later speed.

x= 6.94 *7/5

= 9.7 m/s.