You start with $3 in your investment. Your money doubles every 5 years. How much money will your investment be worth in 30 years?

Question

You start with $3 in your investment. Your money doubles every 5 years. How much money will your investment be worth in 30 years?

a. How many doublings will happen in 30 years?

b. Your investment will be worth in 30 years.

Answer 1

a. Six doublings will occur - after 5, 10, 15, 20, 25, and 30 years.

b. $3 x 64 = $192.

Where did the 64 come from?

You can do it the long way, which is:

$3 x 2 = $6 x 2 = $12 x 2 = $24 x 2 = $48 x 2 = $96 x 2 = $192

Or the shorter way:

$3 x (2 x 2 x 2 x 2 x 2 x 2)

Answer 2

If it doubles every 5 years, there will 6 doublings in 30 years.

After 5 years, the investment will be worth $3 * $2

After 10 years, the investment will be worth $3 * $2 ^2

.

.

.After 30 years the investment will be worth $3 * $2 ^ 6 = $3 * $64 = $192