Question

Suppose an investment of $1,800 doubles in value every 7 years. How much is the investment worth after 42 years?

$151,200
$115,200
$21,600
$25,200

Answer 1

Explanation:

115.200

Answer 2

The investment worth after 42 years is $115200, so option 2 is correct

Solution:

Given, an investment of $1,800 doubles in value every 7 years. We have to find how much is the investment worth after 42 years from the given set of options.

`\begin{array}{l}{\text { Now, after } 7 \text { years } \rightarrow 1800 * 2=3600} \\\\ {\text { After } 14 \text { years } \rightarrow 3600 * 2=7200} \\\\ {\text { After } 21 \text { years } \rightarrow 7200 * 2=14400} \\\\ {\text { After } 28 \text { years } \rightarrow 14400 * 2=28800} \\\\ {\text { After } 35 \text { years } \rightarrow 28800 * 2=57600} \\\\ {\text { After } 42 \text { years } \rightarrow 57600 * 2=115200}\end{array}`

Hence, the investment worth after 42 years is $115200, so option 2 is correct.