Answer:
Apr=6.2%
Step-by-step explanation:
∵ Amount formula in compound interest,
![A=P(1+r)^t](https://tex.z-dn.net/?f=A%3DP%281%2Br%29%5Et)
Where,
P = initial value,
r = rate per period,
t = number of periods,
Here, the given expression that represents the amount of loan after 7 years,
![A=4800(1.06)^7](https://tex.z-dn.net/?f=A%3D4800%281.06%29%5E7)
![=4800(1+0.06)^7](https://tex.z-dn.net/?f=%3D4800%281%2B0.06%29%5E7)
By comparing,
P = $ 4800, r = 0.06, t = 7 years,
If annual rate is 0.06, then, the rate per month = 0.06/12 = 0.005
Time = 7 × 12 = 84 months,
Hence, the amount would be,
![A=4800(1+0.005)^{84}](https://tex.z-dn.net/?f=A%3D4800%281%2B0.005%29%5E%7B84%7D)
Let it is equivalent to the amount obtained in annual compound rate r for 7 years,
![\implies 4800(1+r)^7=4800(1+0.005)^{84}](https://tex.z-dn.net/?f=%5Cimplies%204800%281%2Br%29%5E7%3D4800%281%2B0.005%29%5E%7B84%7D)
![(1+r)^7=(1.005)^{84}](https://tex.z-dn.net/?f=%281%2Br%29%5E7%3D%281.005%29%5E%7B84%7D)
Taking log both sides,
![7\log (1+r) = 84 \log(1.005)](https://tex.z-dn.net/?f=7%5Clog%20%281%2Br%29%20%3D%2084%20%5Clog%281.005%29)
![\log(1+r)=\log(1.005)](https://tex.z-dn.net/?f=%5Clog%281%2Br%29%3D%5Clog%281.005%29)
By graphing calculator,
r = 0.06168 ≈ 0.062 = 6.2 %