Question

8 If a car travels one fourth of the distance at a
speed of 10 m/s and the remaining distance at
a speed of 15 m/s, what is the average speed of
the car?
(1) 30 km/h
(2) 48 km/h
(3) 45 km/h
60 km/h
​

Answer 1

Answer:

the average speed =27.69m/s

Explanation:

let y m be the total distance

case1 } y/4m(d)

speed=10m/s

time1* =y/40

case2 } y/6m(d)

speed =15m/s

*time2=y/90

average speed =total distance /total time

average speed =y /time1+time2

avg .speed= y/time

time1 +time2= 13y/360

avg speed =y×360/13y

avg speed=360/13

avg speed =27.69m/s.

The avg speed is 30 m/s(option 1)