Question

How long did their lesson last?

Answer 1

2 hours 25 minutes

Explanation:

Add minutes step by step.

6:15 --> 7:00

= 45 minutes

7:00 --> 8:00

= 1 hour

8:00 --> 8:40

= 40 minutes

40 min. + 45 min. + 1 hour = 2 hours 25 minutes

Answer 2

There lesson last for 2 hours and 25 minutes.

Explanation:

Minus 840 (8:40) and 615 (6:15) and you get 225 (2:25)