Question

A car covers a distance of 200 km in the first 3 hours, then takes a break of 30 mins and then covers a distance of 50 km in the next 30 mins. Find the average speed of the car in the whole journey?

Answer 1

Step-by-step explanation:

Medium

Answer

Speed of the car =x km /hr

Time taken =t hrs

xt=200

∴t=

x

200

Now, (x+5)(t−2)=200

(x+5)(

x

200

−2)=200

(x+5)(200−2x)=200x

200x−2x

2

+1000−10x=200x

x

2

+5x−500=0

x

2

+25x−20x−500=0

(x+25)(x−20)=0

x=−25,x=20

Speed cannot be negative value, hence, x=20 km/hr