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

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

Explanation
 Speed with which the car travels = 5/7th of its actual speed.
     Distance covered = 42 km
     Time taken to cover the above distance = 1 hour 40 minutes 48 seconds = 1 hr 40 (4/5) min = 126/75 hrs
To find:
     The actual speed of the car = ?
Solution:
 Let the actual speed of the car be x km/hr
Then, (5/7)x *(126/75) = 42
 x = (42 * 7 * 75)/(5 * 126)
 x = 35 km/hr