To calculate the present value of a series of cash flows from a money machine that pays $500 every 6 months for 30 years at an interest rate of 7% compounded semi-annually, we can use the present value of an annuity formula.
Given:
- Payment (PMT) = $500
- Interest Rate (i) = 7% per year = 3.5% per 6 months = 0.035
- Number of Periods (n) = 30 years * 2 = 60 periods
The present value of an annuity formula is:
\[ PV = PMT \times \left(1 - (1 + i)^{-n}\right) / i \]
Plugging in the values:
- PMT = $500
- i = 0.035
- n = 60
Now, substitute these values into the formula:
\[ PV = 500 \times \left(1 - (1 + 0.035)^{-60}\right) / 0.035 \]
Let's calculate the components:
- Calculate \( (1 + 0.035)^{-60} \):
\[ (1 + 0.035)^{-60} = (1.035)^{-60} \approx 0.2151 \]
- Substitute back into the annuity formula:
\[ PV = 500 \times \left(1 - 0.2151\right) / 0.035 \]
Calculate \( 1 - 0.2151 \):
\[ 1 - 0.2151 \approx 0.7849 \]
Now substitute this into the formula:
\[ PV = 500 \times 0.7849 / 0.035 \]
Calculate \( 784.9 / 0.035\):
\[ PV = 500 \times 22413.67 \approx 11206.84 \]
Thus, the present value of the money machine that pays $500 every 6 months for 30 years at a 7% interest rate is approximately $11206.84.