Final answer:
The return on investment is 10%. The simple interest rate on the growth of their investment is also 10%.
Step-by-step explanation:
The return on investment can be calculated using the formula:
Return on Investment = (Ending Value - Initial Value) / Initial Value * 100%
Here, the initial value is $30 and the ending value is $33. Plugging these values into the formula, we get:
Return on Investment = (33 - 30) / 30 * 100%
= 3 / 30 * 100%
= 0.1 * 100%
= 10%
Therefore, the return on investment is 10%.
To find the simple interest rate on the growth of their investment, we need to find the annual growth rate. The annual growth rate can be calculated using the formula:
Growth Rate = (Ending Value - Initial Value) / Initial Value * 100%
Plugging in the values, we get:
Growth Rate = (33 - 30) / 30 * 100%
= 3 / 30 * 100%
= 0.1 * 100% = 10%
Therefore, the simple interest rate on the growth of their investment is 10%.