Question

A man travelled by car for 3 days. He covered 480 km each day. On the first day, he drove for 10 hours at 48 km an hour. On the second day, he drove for 12 hours at 40 km an hour and for the last day he drove for 15 hours at 32 km. What is his average speed?

Answer 1

Total distance covered 480 km.

The first-day distance covered 48 km.

The second-day distance covered 40 km.

The third-day distance covered 32 km.

Number of observations = 3

Average speed = HM = `"N"/(sum 1/"x")`

= `3/((1/48 + 1/40 + 1/32))`

= `3/(((10 + 12 + 15)/480))`

= `(3 xx 480)/37`

= 38.9189

= 38.92 km/hr