Question

A car travelling with 5/7 of its actual speed covers 42 km in 1 hr. 40 min 48 seconds. find the actual speed of the car.

Answer 1

first convert this time into hours

1 hr 40min 48sec= 1 + 40/60 + 48/(60 x 60) hrs
=1+ 2/3 + 4/300
=(300+200+4)/300
=504/300
=126/75 hrs

Let the actual speed be x km/hr.
then
(5x/7) x (126/75) = 42 
so x = (42 x 75 x 7) / (126 x 5)
     x = 35 km/hr


i hope it will help you
regards

Answer 2

Answer:

Step-by-step explanation:

1 hr = 60 min

1 min = 60 secs

So start with 48 secs first which is 48/60 min = 0.8 min

Now, it is 1 hr 40.8 min.

40.8/60 = 0.68 hr

So the time covered is 1.68 hrs.

speed = distance/time

(5/7)*actual speed = 42 km / 1.68 hr

(5/7)*actual speed = 25

actual speed = 25*(7/5) = 35 km/hr