Question

A man drove his car at 80km per hr for 1 and a quarter hrs .He rested for 45mins and then covered 240km, at the same time. Calculate his average speed for the whole journey​

Answer 1

Answer:

Probably 128 km/h, but maybe 98.5 km/h. See below.

Step-by-step explanation:

What does "at the same time" mean?

If it means that he covered the 240 km in the same time as he convered the 80 km, then this is how you solve it:

80 km in 1.25 hour

240 km in 1.25 hour

Total distance: 80 km + 240 km = 320 km

Total time: 1.25 hour + 1.25 hour = 2.5 hour

average speed = (total distance)/(total time) = 320 km / 2.5 hour = 128 km/h

If it means he covered the 240 km in the same time he covered the 80 km plus the rest, then this is how you solve it:

80 km in 1.25 hour

240 km in 1.25 hour + 45 min = 240 km in 1.25 houir + 0.75 hour = 240 km in 2 hour

Total distance: 80 km + 240 km = 320 km

Total time: 1.25 hour + 2 hour = 3.25 hour

average speed = (total distance)/(total time) = 320 km / 3.25 hour = 98.5 km/h