He will need to deposit 520.48 as principal to have enough money to buy the bike.
Explanation:We apply the compound interest formula:
[tex]FV\text{ = P(1 +}\frac{r}{n})^{nt}[/tex]where FV = future value = money for bike = 700
r = rate = 10% = 0.1
n = number of time compounded
n = quaterly = 4
t = time = 3 years
P = principal = amount deposited = ?
[tex]700\text{ = P}(1\text{ + }\frac{0.1}{4})^{4\times3}[/tex][tex]\begin{gathered} 700=P(1+0.025)^{12} \\ 700=P(1.025)^{12} \\ 700\text{ = P(1.3449)} \end{gathered}[/tex][tex]\begin{gathered} \frac{700}{1.3449}=\text{ P} \\ P\text{ = 520.48} \end{gathered}[/tex]He will need to deposit 520.48 as principal to have enough money to buy the bike.