Question

2. A cantaloupe has a radius of 4 inches 98 days after it was planted, and of 9 inches 148
days after it was planted.

(a) Assuming linear growth, write a linear equation that describes growth of radius of
the cantaloupe.
Answer:

(b) Find the radius of the cantaloupe on day 130.

Answer 1

r = ad + b                   (1)

Given:

r = 4 for d = 98

Substituting in (1), we get:

4 = 98a + b                       (2)

r = 9 for d = 148

Substituting in (1), we get:

9 = 148a + b                        (3)

(3) - (2) gives:

50 a = 5

So,

a = 0.1

Substituting in (3), we get:

9 = 14.8 + b

So,

b = - 5.8

Thus, the linear relation is got by substituting in (1) as follows:

r = 0.1 d - 5.8                            (4)

(b)

For d = 130, substituting in (4), we get:

r = (0.1 X 130) - 5.8

= 7.2

So,

Answer is:

7.2