Question

A red maple sapling was 3 feet tall when planted in 2010. Six years later, the tree was 24 feet tall. The growth rate of the tree is constant over time. Find a linear model for the height H (in ft) of the red maple t years after 2010. Let t = 0 represent 2010.H = __________What is the expected height (in ft) of the red maple in 2020?________ ft

Answer 1

Since the growth rate is linear and constant over time, it means that the sequence formed is an arithmetic sequence. The formula for finding the nth term of an arithmetic sequence is expressed as

an = a1 + d(n - 1)

where

a1 is the first term of the sequence

n = number of terms

d = common difference

In this case, n would be t(number of years

From the information given,

a1 = 3

Since the first term is at t = 0 and it represents 2010, six years letter would be represented by t = 7. Thus, we would took for d given that a7 = 24

We have

24 = 3 + d(7 - 1)

24 = 3 + 6d

6d = 24 - 3 = 21

d = 21/6 = 3.5

The linear model would be

an = 3 + 3.5(t - 1)

Substituting H for an, the linear model is

H = 3 + 3.5(t - 1)

At 2020, t = 11

H = 3 + 3.5(11 - 1) = 3 + 35

H = 38