Mastering Ratios and Currency Conversion

If the ratio of boys to girls in a class is 3:2 and there are 15 boys, how many girls are there?

• 10

• 12

• 9

• 8

Answer explanation

The ratio of boys to girls is 3:2. If there are 15 boys, we can set up the proportion: 3/2 = 15/x. Cross-multiplying gives 3x = 30, so x = 10. Therefore, there are 10 girls in the class.

Divide £60 in the ratio of 2:3.

• £24 and £36

• £30 and £30

• £20 and £40

• £25 and £35

Answer explanation

To divide £60 in a ratio of 2:3, first add the parts: 2 + 3 = 5. Then, calculate each part: £60 ÷ 5 = £12. Multiply by the ratio parts: 2 × £12 = £24 and 3 × £12 = £36. Thus, the correct answer is £24 and £36.

Convert £100 to Euros if the exchange rate is £1 = €1.15.

• €115

• €110

• €120

• €130

Answer explanation

To convert £100 to Euros at the rate of £1 = €1.15, multiply 100 by 1.15. This gives €115, which is the correct answer.

A recipe requires ingredients in the ratio 4:5:6. If you have 20 ounces of the first ingredient, how much of the third ingredient do you need?

• 24 ounces

• 30 ounces

• 36 ounces

• 40 ounces

Answer explanation

The ratio of the ingredients is 4:5:6. If you have 20 ounces of the first ingredient (4 parts), then each part is 5 ounces. The third ingredient (6 parts) would be 6 * 5 = 30 ounces. Thus, you need 36 ounces of the third ingredient.

If a car travels 60 miles in 1 hour, what is the ratio of miles to hours?

• 60:1

• 1:60

• 30:1

• 1:30

Answer explanation

The car travels 60 miles in 1 hour, so the ratio of miles to hours is 60:1. This means for every 1 hour, the car covers 60 miles, making 60:1 the correct choice.

A bag contains red and blue marbles in the ratio 5:3. If there are 40 marbles in total, how many are blue?

• 15

• 20

• 25

• 30

Answer explanation

The ratio of red to blue marbles is 5:3, meaning for every 8 marbles, 3 are blue. With 40 marbles total, the number of blue marbles is (3/8) * 40 = 15. Thus, the correct answer is 15.

Convert 200 US dollars to British pounds if the exchange rate is $1 = £0.75.

• £150

• £160

• £170

• £180

Answer explanation

To convert 200 US dollars to British pounds at an exchange rate of $1 = £0.75, multiply 200 by 0.75. This gives you 200 * 0.75 = £150, making £150 the correct answer.

If the ratio of cats to dogs in a shelter is 7:4 and there are 28 cats, how many dogs are there?

• 16

• 14

• 12

• 10

Answer explanation

The ratio of cats to dogs is 7:4. With 28 cats, we set up the proportion 7/4 = 28/x. Cross-multiplying gives 7x = 112, so x = 16. Thus, there are 16 dogs.

Divide 90 ounces of juice into a ratio of 1:2.

• 30 ounces and 60 ounces

• 45 ounces and 45 ounces

• 60 ounces and 30 ounces

• 20 ounces and 70 ounces

Answer explanation

To divide 90 ounces in a ratio of 1:2, add the parts (1+2=3). Each part is 90/3=30 ounces. Thus, the first part is 30 ounces and the second part is 60 ounces, making the correct choice 30 ounces and 60 ounces.

A map uses a scale of 1:100,000. If a distance on the map is 5 cm, what is the actual distance in miles?

• 3.1 miles

• 5 miles

• 6.2 miles

• 7.5 miles

Answer explanation

To find the actual distance, multiply the map distance by the scale factor: 5 cm x 100,000 = 500,000 cm. Convert cm to miles: 500,000 cm ÷ 160,934.4 cm/mile ≈ 3.1 miles. Thus, the correct answer is 3.1 miles.