Question 998069
Let's call the number of hours he drives on the first day x.
Then the second day he drives x + 3.
The third day he drives 2x - 3.

Now add those up...
x + x + 3 + 2x - 3 = 20
4x = 20
x = 5
x + 3 = 8
2x - 3 = 7
5, 8, 7 hours each day.