Numeracy: Ratios and Percentages Flashcards

A school has a ratio of teachers to students of 1:18. If there are 540 students in the school, how many teachers are there?

Answer: 30

The ratio 1:18 means there is 1 teacher for every 18 students. To find the total number of teachers, divide the total number of students by the student part of the ratio: 540 students ÷ 18 = 30 teachers.

A survey of 300 people found that 65% preferred coffee over tea. How many people preferred coffee?

Answer: 195

To find 65% of 300, convert the percentage to a decimal (65% = 0.65) and multiply it by the total number of people. Calculation: 0.65 * 300 = 195.

After a 15% discount, the price of a jacket is $170. What was the original price of the jacket?

Answer: $200.00

A 15% discount means the sale price is 85% (100% - 15%) of the original price. To find the original price, divide the sale price by the percentage paid (as a decimal): $170 ÷ 0.85 = $200.

In a bag of 50 marbles, 15 are red. What percentage of the marbles are red?

Answer: 30%

To calculate the percentage, create a fraction representing the red marbles out of the total (15/50). Then, multiply this fraction by 100 to convert it to a percentage. Calculation: (15 ÷ 50) * 100 = 30%.

A sports team won 12 games and lost 8 games. Which of the following represents the simplified ratio of wins to losses?

Answer: 3:2

The initial ratio of wins to losses is 12:8. To simplify a ratio, find the greatest common factor (GCF) of both numbers. The GCF of 12 and 8 is 4. Divide both parts of the ratio by 4: (12 ÷ 4) : (8 ÷ 4) = 3:2.

A restaurant bill is $80. A 10% Goods and Services Tax (GST) is added to this amount. The customer then leaves a 5% tip based on the new total (including GST). What is the final amount paid?

Answer: $92.40

This is a multi-step problem. First, calculate the GST: 10% of $80 is $8. Add this to the bill: $80 + $8 = $88. Now, calculate the tip on this new total: 5% of $88 is $4.40. Finally, add the tip to the taxed amount: $88 + $4.40 = $92.40.