Here are the solutions to your questions:
Question 2
2.1
Step 1: Convert the nominal interest rate of 13% p.a. compounded quarterly to an equivalent nominal interest rate compounded monthly.
We use the formula for equivalent interest rates:
(1+m1inom1)m1=(1+m2inom2)m2
Given inom1=0.13 (13%), m1=4 (quarterly). We want to find inom2 (monthly rate), with m2=12.
(1+40.13)4=(1+12imonthly)12
Step 2: Calculate the left side of the equation.
(1+0.0325)4=(1.0325)4=1.13647990625
Step 3: Solve for imonthly.
1.13647990625=(1+12imonthly)12
Take the 12th root of both sides:
(1.13647990625)1/12=1+12imonthly
1.010720333=1+12imonthly
0.010720333=12imonthly
imonthly=0.010720333×12
imonthly=0.128643996
Expressed as a percentage, this is 12.8643996%≈12.86%.
Thus, the effective interest rate is 12.86%p.a.compoundedmonthly.
2.2
Step 1: Identify the known values for the present value annuity formula.
Loan amount (P) = R600 000
Monthly instalment (x) = R9 000
Monthly interest rate (i) = 120.128643996=0.010720333
We need to find the number of payments (n).
The present value annuity formula is:
P=ix[1−(1+i)−n]
Step 2: Substitute the values into the formula.
600000=0.0107203339000[1−(1+0.010720333)−n]
Step 3: Solve for n.
600000×0.010720333=9000[1−(1.010720333)−n]
6432.1998=9000[1−(1.010720333)−n]
90006432.1998=1−(1.010720333)−n
0.71468886=1−(1.010720333)−n
(1.010720333)−n=1−0.71468886
(1.010720333)−n=0.28531114
Take the natural logarithm of both sides:
−nln(1.010720333)=ln(0.28531114)
−n×0.01066310=−1.254790
n=−0.01066310−1.254790
n=117.674
Since n is not an integer, there will be 117 full instalments of R9 000.
The number of instalments of R9 000 that must be paid is 117.
2.3
Step 1: Calculate the outstanding balance after 117 payments.
The balance outstanding after k payments (Bk) is given by:
Bk=P(1+i)k−xi(1+i)k−1
Using P=600000, x=9000, i=0.010720333, and k=117:
B117=600000(1.010720333)117−90000.010720333(1.010720333)117−1
First, calculate (1.010720333)117≈3.437990.
B117=600000(3.437990)−90000.0107203333.437990−1
B117=2062794−90000.0107203332.437990
B117=2062794−9000×227.4170
B117=2062794−2046753
B117=16041
Step 2: Calculate the final payment.
The final payment will be this outstanding balance plus one month's interest. This payment occurs at the end of the 118th month.
Finalpayment=B117(1+i)
Finalpayment=16041(1+0.010720333)
Finalpayment=16041(1.010720333)
Finalpayment=16213.38
The final payment will be R16213.38.
2.4
Step 1: Calculate the total amount paid.
Total cost = (Number of full payments × Instalment amount) + Final payment
Totalcost=(117×R9000)+R16213.38
Totalcost=R1053000+R16213.38
Totalcost=R1069213.38
The car cost Jake in total R1069213.38.
Question 3
3.1
Step 1: Identify the nominal interest rate and compounding frequency.
Nominal rate (inom) = 0.14 (14%)
Number of compounding periods per year (m) = 12 (monthly)
Step 2: Use the formula for effective annual interest rate.
(1+ieff)=(1+minom)m
(1+ieff)=(1+120.14)12
(1+ieff)=(1+0.01166666666)12
(1+ieff)=(1.01166666666)12
(1+ieff)=1.149342026
Step 3: Calculate the effective annual rate.
ieff=1.149342026−1
ieff=0.149342026
Expressed as a percentage, this is 14.9342026%≈14.93%.
The effective interest rate per annum is 14.93%.
3.2
Step 1: Identify the known values for the future value annuity formula.
Future Value (FV) = R7003007.22
Monthly payment (x) = R800
Nominal interest rate = 16% p.a. compounded monthly.
Monthly interest rate (i) = 120.16=0.01333333333
We need to find the number of payments (n).
The future value annuity formula is:
FV=ix[(1+i)n−1]
Step 2: Substitute the values into the formula.
7003007.22=0.01333333333800[(1+0.01333333333)n−1]
Step 3: Solve for n.
7003007.22×0.01333333333=800[(1.01333333333)n−1]
93373.4296=800[(1.01333333333)n−1]
80093373.4296=(1.01333333333)n−1
116.716787=(1.01333333333)n−1
117.716787=(1.01333333333)n
Take the natural logarithm of both sides:
ln(117.716787)=nln(1.01333333333)
4.768390=n×0.0132440
n=0.01324404.768390
n=360
Skomota made 360 payments.
3 done, 2 left today. You're making progress.