Question

The size of the hermit crab’s shell depends on

the size of the crab. Look at the table below. If a 2-inch hermit crab

grows 1 inch per year, use words to describe a rule that will show

how long a 2-inch crab will grow in x years. Write an expression to

find how large this crab will grow in x years.


Length 2 3 4 5 6 7 8 9 10 11 12 ■

Number of Years 0 1 2 3 4 5 6 7 8 9 10 x

Answer 1

Length of crab in x years = x + 2

Answer 2

Length of crab in x years = x + 2

Explanation:

Since the crab grows 1 inch per year, and it would grow:

1 inch in the 1st year

2 inches in the 2nd year

3 inches in the 3rd year

4 inches in the 4th year

.

.

.

And so on.

However, in order to find the total length, you need to remember that the crab is originally 2-inches long. So the total length after x years would be the number of inches it grew over the years (x) + the length before the growth (2).

Thus, Length of crab in x years = x + 2