Question

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.

Answer 1

Let actual speed of car be x
Car is travelling 5 /7 of x
Distance travelled =42 km
Time taken = 1 hr 40 min 48 sec =100 .80 min
speed =distance /time
5/7 x =42 /100. 80
504 x =294
504/ 294 =x
1.71428...
1.7143 km /hr =x ...

Sorry for any mistake

Answer 2

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

Time taken = 1 hr 40 min 48 sec

=1 hr 40 4/5 min

= 1 51/75 hrs

=126/75 hrs

Let the actual speed be 'x' kmph

5/7 of actual speed →5x/7

Speed×time = distance

5x/7 × 126/75 = 42 km

x = (42×75×7)/(126×5)

x = 22050/630

x = 35 km/hr

Therefore,actual speed = 35 km/hr