Question

The total volume of a tree increases

8% each year. What will its volume be
after 7 years if its volume is 5 cubic
meters now?
A) 5(1.08)^7
B) 5(7)(0.08)
C) 5(0.08)^7
D) 5(7)(1.08)

Answer 1

A

Explanation:

it all starts with 5 m³.

after one year this will be

5 × 1.08

as the original 5 m³ have increased by 8% (= multiplication by 1.08, as 8% = 0.08, and adding 8% means 100% + 8% = 1 + 0.08 = 1.08).

after the second year we will see another increase by 8% compared to the previous year.

so,

(5 × 1.08) × 1.08 = 5(1.08)²

...

and so, after the nth year, the volume is

5(1.08)^n

therefore, after 7 years means n = 7, and we get

5(1.08)⁷