Question

1p

A man travelled by a car for 3 days. He covered 1080 km each day. He
drove the first day 10 hours at 108 km per hour, the second day 12 hours at
90 km per hour and third day 18 hours at 60 km per hour. What has his
average speed.
O 81 km per hour
O 80km per hour
O 83 km per hour
82 km per hour​

Answer 1

O 81 km per hour

Step-by-step explanation

Given parameters:

Number of days traveled = 3 days

Distance covered on the first day = 1080km

Time of travel = 10hrs

Rate of travel = 108km/hr

Time of travel on second day = 12hrs

Rate of travel = 90km/hr

Time of travel on third day = 18hrs

Rate of travel = 60km/hr

Unknown

Average speed = ?

To find the average speed, we sum the distances and divide by the sum of the time.

Average speed =
`(Total distance)/(total time)`

we do not know the second and third distances;

Distance = speed x time

D2 = 90 x 12 = 1080km

D3 = 60 x 18 = 1080km

Now;

Average speed =
`(1080 + 1080 + 1080 )/(10 + 12 + 18 )`

Average speed =
`(3240)/(40)` = 81km/hr

The average speed is 81km/hr