Answer:
A triangle can have these three side lengths.
He traveled 40 feet per second
the board would be 4.85 feet
2.5(t - 2) - 6 = 9
2.5(t - 2) = 9 + 6 = 15
t - 2 = 15/2.5 = 150/25 = 6
t = 6 + 2 = 8
Answer: 8
Check: 2.5(8 - 2) - 6 = 2.5(6) - 6 = 1.5(6) = 9 good
