#### Interest, compound growth, appreciation, depreciation

1.
Use the formulae for simple interest to calculate the value of each letter:
Number
Principal
Interest rate
Time
Interest
Amount
R
%
years
R
R
1.1
31 450
3,5
5
a
b
1.2
110 600
12
3
c
d
1.3
1 250
5,5
2
e
f
1.4
14 800
g
7
h
21 016
1.5
12 500
j
5
k
28 250
1.6
21 400
m
3
n
27 178
1.7
p
3,75
6
281 250
1 531 250
1.8
r
8
3
252
1 302
1.9
t
6
7
1 050
3 550
1.10
13 700
11,25
v
w
21 406,25
1.11
81 650
9
x
y
96 347
1.12
110 250
11,5
z
114 108,80
aa
1.13
ab
7,5
4
3 750
16 250
2.
Use the formulae for compound interest to calculate the value of each letter below:
Number
Principal
Interest rate
Time
When
Interest
Amount
R
%
years
compounded
R
paid
2.1
13 250
4
3
yearly
a
b
2.2
65 000
8
4
yearly
c
d
2.3
116 000
e
6
annually
f
235 165,20
2.4
12 800
g
3
quarterly
h
24 335,46
2.5
60 000
j
4,5
monthly
27 838,18
k
2.6
28 400 000
m
2,5
half-yearly
5 739 634
n
2.7
p
10
4
quarterly
q
22 267,58
2.8
r
15
8
quarterly
s
4 061 980
2.9
t
22
3
quarterly
u
155 899
2.10
v
15
15
monthly
w
2 151 957
2.11
180 000
x
3,5
monthly
156 392,5
y
2.12
35 050
z
2,5
quarterly
aa
8 734,58
2.13
ab
8
4
biannually
ac
3 422 244
3. A painting is valued at R800 in 1950. It appreciates at 8% p.a. What is the value of the painting in 2009?

4. In 2008 a man buys a lorry at R1 000 000. The lorry depreciates at 8% p.a. What will the
the value of the lorry be in 2018?

5. In 1952 a coin collection is valued at R120. The collection appreciates at 7% p.a.
What is the value of the collection in 2008?

6. The value of a motorcar is R750 000 in 2007. It depreciates at 18% p.a. Calculate the value of the car
in 2010.

7. In 1970 an aeroplane is valued at \$80 000, US dollars. The aeroplane depreciates at 6,5% p.a.
7.1 Calculate the value of the aeroplane, in US dollars \$, in 2009.
7.2 In 1970 the exchange rate is \$1 = R0,85 and in 2009 the exchange rate is \$1 = R10,42.
Calculate the value of the aeroplane in Rand in 1970 and in 2009.
7.3 What was the percentage rate of change in the Rand value of the aeroplane from 1970 to 2009?

8. An art collection is valued at R550 000 in 1960. In 2008 the same collection is valued at
R102 224 812. At what percentage rate did the collection appreciate?

9. The value of a car in 1999 is R240 000. In 2009 the value of the same car is
R47 250. At what percentage rate did the value of the car depreciate?

10. Tom buys a bed. The bed costs R2 850. There are three options available. Help Tom to
choose the best option available.
Option 1: Pay cash and receive a discount of 10%.
Option 2: Pay a deposit of 15% and the remainder over 24 months at an interest rate of 12,5%.
Option 3: Borrow the necessary amount at the bank at an interest rate of 15% p.a.
compounded monthly for 2 years and pay cash for the bed.