Numeracy: Number and Algebra Flashcards

A recipe for concrete requires cement, sand, and gravel in the ratio of 1:2:4. If a builder uses 10 bags of sand, how many bags of gravel will be needed?

Answer: 20 bags

The ratio of sand to gravel is 2:4. This can be simplified to 1:2, meaning for every one part of sand, two parts of gravel are needed. If the builder uses 10 bags of sand, they will need twice that amount of gravel, which is 10 x 2 = 20 bags.

A smartphone is on sale for 20% off its original price. If the original price was $850, what is the sale price?

Answer: $680

First, calculate the discount amount: 20% of $850 is (20/100) * 850 = $170. Then, subtract the discount from the original price to find the sale price: $850 - $170 = $680.

Which of the following calculations results in the smallest value?

Answer: 30 - 36 ÷ 3

To solve this, apply the order of operations (BIDMAS/BODMAS) to each option: A) 15 + 10 = 25 B) 30 - 12 = 18 C) 8 x 4 = 32 D) 25 - 10 = 15 The smallest value is 18.

A catering company charges a flat fee of $150 plus $25.50 per person. If 'p' represents the number of people, which equation correctly calculates the total cost (C)?

Answer: C = 25.50p + 150

The total cost (C) is the sum of the fixed flat fee ($150) and the variable cost, which is the price per person ($25.50) multiplied by the number of people (p). This is represented by the equation C = 25.50p + 150.

Kaelan's bank account balance was -$45.60. He then deposited $100 into the account. What is his new bank account balance?

Answer: $54.40

Starting with a negative balance of -45.60, a deposit of $100 is an addition. The calculation is -45.60 + 100.00, which equals $54.40. The account is now in credit.

A survey of 200 students found that 3/4 of them play a sport. How many students do not play a sport?

Answer: 50

If 3/4 of the students play a sport, then 1/4 of the students do not. To find the number of students who do not play a sport, calculate 1/4 of 200. This is 200 ÷ 4 = 50 students.