The world record for the men’s marathon, 42 km, is 2 hours and 3 minutes.

average speed: 20.5km/h

Explanation:

The following question is missing:

What was the average speed of the record-setting runner in km/h?

To answer this, first convert 3 minutes into hours. We know that 60 minutes make an hour, using this conversion factor we get:

3 minutes * (1 hour/60 minutes) = 0.05 hours

Next add this result to the 2 hours:

2 hours and 3 minutes = 2 h + 0.05 h = 2.05 hours

The average speed is obtained dividing the distance traveled by the time elapsed:

42 km/2.05 hours ≈ 20.5km/h

since you're a real machine, your ama is always less than your ima, because you can never totally eliminate friction.

i believe the answer would be:

d. violin, clarinet, french horn, and tuba