Solve the class boundary

Step 1: Calculate the lower class boundary for each class. The lower class boundary is found by subtracting $0.5$ from the lower limit of each class.

• For $0-9$: Lower boundary $= 0 - 0.5 = -0.5$ • For $10-19$: Lower boundary $= 10 - 0.5 = 9.5$ • For $20-29$: Lower boundary $= 20 - 0.5 = 19.5$ • For $30-39$: Lower boundary $= 30 - 0.5 = 29.5$ • For $40-49$: Lower boundary $= 40 - 0.5 = 39.5$

Step 2: Calculate the upper class boundary for each class. The upper class boundary is found by adding $0.5$ to the upper limit of each class.

• For $0-9$: Upper boundary $= 9 + 0.5 = 9.5$ • For $10-19$: Upper boundary $= 19 + 0.5 = 19.5$ • For $20-29$: Upper boundary $= 29 + 0.5 = 29.5$ • For $30-39$: Upper boundary $= 39 + 0.5 = 39.5$ • For $40-49$: Upper boundary $= 49 + 0.5 = 49.5$

The class boundaries are: • $0-9$: $\boxed{-0.5 to 9.5}$ • $10-19$: $\boxed{9.5 to 19.5}$ • $20-29$: $\boxed{19.5 to 29.5}$ • $30-39$: $\boxed{29.5 to 39.5}$ • $40-49$: $\boxed{39.5 to 49.5}$