Question

The price of apples went from $0.30 per lb to $0.90 per lb in three years. Find the rate of change of the price of apples.

Answer 1

90c-30c=60cent change

60cents/3years=20cents/year

It changed 20cents a year

Answer 2

Hence, the rate of change of the price of apples is:

$ 0.20 per year.

Explanation:

Let P denote the price of apples.

It is given that the initial price of apples is: $ 0.30 per lb.

i.e. P(0)=$ 0.30 per lb.

Also, the price of the apples after three years is: $ 0.90 per lb.

i.e. P(3)=$ 0.90 per lb.

Hence, the rate of the change of the price of apples is calculated by:

`Rate\ of\ change=(P(3)-P(0))/(3-0)`

Now on putting the value in the formula we obtain:

`Rate\ of\ change=(0.90-0.30)/(3-0)\\\\\\Rate\ of\ change=(0.60)/(3)\\\\\\Rate\ of\ change=0.20`

The rate of change is:

$ 0.20 per year.