Question

some part of journey of 555 km was completed by car with speed 60 km/hr.If speed of car then increased by 15 km/hr and the journey is completed it takes 8 hours to reach.Find time taken and distance covered by 60 km/hr speed.

Answer 1

Let x km distance covered with speed 60 km/h
and (555 - x) km distance with speed (60 + 15) = 75 km/h
Total time taken to complete journey = 8 hrs

∵ time = distance/speed
∴ total time taken to complete journey = time taken to cover distance x km with speed 60 km/h + time taken to cover distance (555 - x) km with speed 75 km/h
⇒ 8 = x/60 + (555 - x)/75
⇒ 8 = (5x + 4 × 555 - 4x )/300
⇒ 8 = (x + 2220)/300
⇒ 8 × 300 = x + 2220
⇒ 2400 - 2220 = x
⇒ x = 180 km

Hence , distance covered by speed = 180 km

Answer 2

Hello Dear.

Good Question and Keep Progressing.


Given Conditions---
 
Original Speed = 60 k/hr.

Let the Distance covered by the car with a speed of 60 km/hr be x km.

  Using the Formula,
          Speed = Distance/time
   
     →Time(T1) = Distance/Speed
                         = x/60 hr.

→ New Speed = Original Speed of the Car + 15 km/hr.
                    = 60 +15
                    = 75 km/hr.

Distance covered by the Car with an Speed of 75 km/hr

 = Total Distance - Distance covered by the car with an speed of 60 km/hr.
 = (555 - x)hr.

Thus, Time(T2) = (555 - x)/75


According to the Question,

                             T1 + T2  =  8
                    x/60 + (555-x)/75 = 8
                 (5x + 2220 - 4x)/300 = 8  [ Taking L.C.M.]
                       x + 2220 = 8 × 300
                        x = 2400 - 2220
                        x = 180 km.

Thus, the distance covered by the car with the speed of 0 km/hr is 180 km.

For time taken,
     
     Time = Distance/Speed
   
         Time = x/60
         Time = 180/60
          Time = 3 hr.

Thus, the time taken by the car to cover the distance of 180 k with an Speed of 60 km/hr is 3 Hours.


I anticipate it will helps u.

Have a Marvelous Day.