1. Write the cost function for Acme's service:
C(t) = 100 + 30t
2. Write the cost function for Hank's Movers:
H(t) = 55t
3. Set up the inequality \( 55t < 100 + 30t \).
4. Subtract \( 30t \) from both sides to isolate \( t \):
55t - 30t < 100
25t < 100
5. Solve for \( t \) by dividing both sides by 25:
t < 4
So, it costs less to hire Hank's Movers for lengths of time \( t < 4 \) hours.