You must be able to:
Calculate n in the formula

Calculation of n

Notes:
In 2³ = 8 we are able to say that:
3 = log₂8

The “ log” operator is extremely useful in working out the index value of a power.

To solve for x

Solve:

Exercise

1. A boy inherits Rx from his father. He wishes to invest this amount until it doubles in value.
If the interest rate is 15% p.a. compounded annually, for how many completed years must he invest his money?

2. Determine how long, in years, it will take for a vehicle to decrease to 25% of its original value, if the rate of depreciation, based on the reducing balance, is 21% p.a.

3. The population of a certain species of bats was estimated to be decreasing at an annual rate of 10 % of its total at the beginning of each year.
If the total population at the beginning of a year was 40000, calculate after how many years it would decrease to 1000.