Answer:
It will need $ 107,120.321 dolalr per year to achieve his retirement goal
Explanation:
We first must calcualte the prsent value of the 25 payments with equal worth of 60,000 dollar of today.
First we move the 60,000 forward 10 years
[tex]Principal \: (1+ r)^{time} = Amount[/tex]
Principal 60,000.00
time 10.00
rate 0.05000
[tex]60000 \: (1+ 0.05)^{10} = Amount[/tex]
Amount 97,733.68
Now, we calculate the present value of an annuity considering this 5% inflation
[tex]C_0 \times \frac{(1+r)^n-(1+g)^n}{r-g} = PV[/tex]
g 0.05
r 0.08
C 97,734
n 25
$ 1,778,492.341
Then, decrease this by the amounnt already saved by our father:
[tex]Principal \: (1+ r)^{time} = Amount[/tex]
Principal 105,000.00
time 10.00
rate 0.08000
[tex]105000 \: (1+ 0.08)^{10} = Amount[/tex]
Amount 226,687.12
Additional saving needed:
1,778.492-34 - 226,687.12 = 1.551.805,22
Now, we solve the annual saving to achieve this future value:
[tex]PV \div \frac{(1+r)^{time} -1}{rate} = C\\[/tex]
PV 1,551,805.22
time 10
rate 0.08
[tex]1551805.22 \div \frac{(1+0.08)^{10} -1}{0.08} = C\\[/tex]
C $ 107,120.321