Question

The table shows how the lengths of four pet lizards are changing over time.

Time
(years) Lizard Name and Length (centimeters)
Chuck Betty Snapper Rocky
0 9 7 12 11
1 10 8 14 14
2 12 10 17 17
3 16 13 19 20
4 24 17 22 23
Which lizard is growing at a constant rate?

A.
Chuck

B.
Betty

C.
Snapper

D.
Rocky

Answer 1

To determine which lizard is growing at a constant rate, we need to look at the changes in length for each lizard over the years and see if they all grow by the same amount each year.

Let's calculate the growth for each lizard year by year:

- **Chuck**:
- Year 0 to 1: 10 - 9 = 1 cm
- Year 1 to 2: 12 - 10 = 2 cm
- Year 2 to 3: 16 - 12 = 4 cm
- Year 3 to 4: 24 - 16 = 8 cm
- Growth is not constant.

- **Betty**:
- Year 0 to 1: 8 - 7 = 1 cm
- Year 1 to 2: 10 - 8 = 2 cm
- Year 2 to 3: 13 - 10 = 3 cm
- Year 3 to 4: 17 - 13 = 4 cm
- Growth is not constant.

- **Snapper**:
- Year 0 to 1: 14 - 12 = 2 cm
- Year 1 to 2: 17 - 14 = 3 cm
- Year 2 to 3: 19 - 17 = 2 cm
- Year 3 to 4: 22 - 19 = 3 cm
- Growth is not constant.

- **Rocky**:
- Year 0 to 1: 14 - 11 = 3 cm
- Year 1 to 2: 17 - 14 = 3 cm
- Year 2 to 3: 20 - 17 = 3 cm
- Year 3 to 4: 23 - 20 = 3 cm
- Growth is constant (3 cm each year).

Based on this analysis, the lizard that is growing at a constant rate is:

**D. Rocky**