Question 25 of 49intermediate🔧 ApplyLong Answer5 marks

Suppose a plant has height 1.751.75 feet and it grows by 0.50.5 feet each month.

(i)

Find the height after 77 months.

Answer

(i) Height after 7 months:

The initial height of the plant is 1.751.75 feet, and it grows by 0.50.5 feet each month.

Given: Initial height =1.75= 1.75 feet, Growth rate =0.5= 0.5 feet/month, Time =7= 7 months

Formula:

Height=Initial height+(Growth rate×Time)\text{Height} = \text{Initial height} + (\text{Growth rate} \times \text{Time})

Substitution:

Height=1.75+(0.5×7)\text{Height} = 1.75 + (0.5 \times 7)

Calculation:

Height=1.75+3.5=5.25 feet\text{Height} = 1.75 + 3.5 = 5.25 \text{ feet}

∴ The height after 7 months is 5.25 feet.

(ii)

Make a table of values for tt varying from 00 to 1010 months and show how the height, hh, increases every month.

Answer

(ii) Table of values:

The height increases by a constant amount of 0.50.5 feet every month. The table of values for time tt (in months) and height hh (in feet) is as follows:

tt012345678910
hh1.752.252.753.253.754.254.755.255.756.256.75

As shown in the table, the height increases by 0.5 feet every month. This constant increase over equal intervals is a key characteristic of the data provided.

(iii)

Find an expression that relates hh and tt, and explain why it represents linear growth.

Answer

(iii) Expression and explanation:

The expression that relates height hh and time tt is:

h=1.75+0.5th = 1.75 + 0.5t

This represents linear growth because, as the value of tt increases by a fixed number (one month), the value of the height hh increases by a fixed number (0.50.5 feet). A linear pattern where a quantity increases by a constant amount over equal intervals represents linear growth.

∴ The expression is h=1.75+0.5th = 1.75 + 0.5t, representing linear growth.

Explanation

The initial height is 1.751.75 feet, and the plant grows 0.50.5 feet per month.

(i) After 77 months, the height is:

1.75+(0.5×7)=5.25 feet1.75 + (0.5 \times 7) = 5.25 \text{ feet}

(ii) The table shows the height at each month from 00 to 1010, increasing by 0.50.5 feet each time.

(iii) The expression is derived from the initial value plus the rate of growth times the time:

h=1.75+0.5th = 1.75 + 0.5t

It represents linear growth because the quantity increases by a constant amount over equal intervals, as defined in the text.