Answer: He need to add approximately $ 426.63 to his account to reach the desired balance of $7000.
Step-by-step explanation:
Here, the principal amount, P = $ 3000,
Semiannual rate of interest, r = 8 %
Time, t = 10 years,
Hence, the amount after 10 years, which is compounded with the semiannual rate of 8% for 10 years,
[tex]A=P(1+\frac{r/2}{100})^{2t}[/tex]
[tex]=3000(1+\frac{8/2}{100})^{20}[/tex]
[tex]=3000(1+\frac{4}{100})^{20}[/tex]
[tex]=3000(1+0.04)^{20}[/tex]
[tex]3000\times (1.04)^{20}[/tex]
[tex]=3000\times 2.19112314303=\$ 6573.3694291[/tex]
Thus, the amount, need to add in the balance to reach the amount of $ 7000 = 7000 - 6573.3694291 = 426.6305709 ≈ $ 426.63
⇒ He need to add approximately $ 426.63 to his account to reach the desired balance of $7000.
⇒ Option B is correct.