Simple Interest

Simple Interest I = Prt

I = simple interest
P = principal
r = rate of simple interest
t = time or term in years

Simple Amount S = P(1 + rt)

S = original principal + interest earned
S = P + Prt

Example :-
RM10 000 is invested for 4 years 9 month in a bank earning a simple interest rate of 10% per annum. Find the simple amount at the end of the investment period

P = RM10 000
r = 10%
t = 4.75 years

I = Prt
I = 10 000 x 0.1 x 4.75
= RM4750

S = P + I
S = 10 000 + 4750
= RM14 750

OR

S = P(I + rt)
S = 10000 (1+0.1x4.75)
= RM14750

Fraction and Percent

1/100 = 1% 1/50 = 2% 1/25 = 4% 1/20 = 5%

1/10 = 10% 1/5 = 20% 1/4 = 25% 2/5 = 40%

1/2 = 50% 3/5 = 60% 1 = 100% 3/4 = 75%

Rules for Divisibility

A number can be divided by :-

2 if the last digit is 0, 2, 4, 6 or 8
3 if the sum of the digits is divisible by 3
4 if the last two digits are divisible by 4
5 if the last digits is 0 or 5
6 if the number is even and the sum of the digits is divisible by 3

Decimal Equivalents

1/6 = 0.0625 1/9 = 0.1111 5/16 = 0.3125

3/8 = 0.375 1/5 = 0.2 13/4 = 3.25

30/100 = 0.3 100/20 = 5 15/4 = 3.75

MARK-UP

Definition: A percentage added to the cost to get the retail selling price.
Also Known As: markon, markup

Examples: A widget bought for $5 and sells for $10 has a mark-up of 100%. (Add $5 to the $5 cost to get the price.) A widget bought for $2, which sells for $3, has a mark-up of 50%, (Add $1 to the $2 cost to get the price.)

Retail math is often used in various ways by store owners, managers, retail buyers and other retailing employees. It is used to evaluate inventory purchasing plans, analyze sales figures, add on markup and apply markdown pricing to plan stocks.

Cost of Goods + Markup = Retail PriceRetail Price - Cost of Goods = MarkupRetail Price - Markup = Cost of Goods