RATIO, PROFIT AND LOSS
Examples of ratios
A class has 45 girls and 40 boys. The ratio of number of boys to the number of girls = 40: 45
A football ground 100 𝑚 long and 50 𝑚 wide. The ratio of length to the width = 100: 50
- 40: 45 = 8: 9
- 100: 50 = 2: 1
A Ratio in its Simplest Form
Express a ratio in its simplest form
Example 1
Simplify the following ratios, giving answers as whole numbers
RATIO PROFIT AND LOSS
A Given Quantity into Proportional Parts
Divide a given quantity into proportional parts
To increase or decrease a certain quantity in a given ratio, multiply the quantity with that ratio
Example 3
- Increase 6 𝑚 in the ratio 4 ∶ 3
- Decrease 800 /− in the ratio 4 ∶ 5
Solution
Profits and Loss
you buy something and then sell it at a higher price, then you have a
profit which is given by: Profit = selling price − buying price
you buy something and then sell it at a lower price, then you have a
loss which is given by: Loss = buying price − selling price
The profit or loss can also be expressed as a percentage of buying price as follows:
Percentage Profit and Percentage Loss
Calculate percentage profit and percentage profit and percentage loss
Example 4
Therefore the profit obtained is 500,000/-
Example 5
Solution
To calculate interest, we use interest rate (R) given as a percentage and is usually taken per year or per annum (p.a)
Example 6
Calculate the simple interest charged on the following
850, 000/− at 15% per annum for 9 months
200, 000/− at 8% per annum for 2 years
Real Life Problems Related to Simple Interest
Solve real life problems related to simple interest
Example 7
Mrs.
Mihambo deposited money in CRDB bank for 3 years and 4 months. A t the
end of this time she earned a simple interest of 87, 750/− at 4.5% per
annum. How much had she deposited in the bank?
Solution
Change months to years
