Ratios Introduction — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A map scale says 1 inch equals 50 miles. Two cities are 4 inches apart on the map. How many real miles apart are they?
A) 200 miles
B) 150 miles
C) 100 miles
D) 250 miles
4 inches times 50 miles per inch equals 200 actual miles.
2. A paint mix uses red, blue, and white in a 2:3:5 ratio. If 30 cups of paint are made, how many cups are blue?
A) 6 cups
B) 9 cups
C) 12 cups
D) 15 cups
Total parts 10; 30 divided by 10 is 3, so blue gets 3 times 3 equals 9.
3. A recipe serves 4 people using 2 cups of rice. To serve 10 people, how many cups of rice are needed?
A) 4 cups
B) 4.5 cups
C) 5 cups
D) 6 cups
2 divided by 4 is 0.5 cups per person; 0.5 times 10 equals 5.
4. A scale model has a ratio of 1:24. The real car is 192 inches long. How long is the model?
A) 6 inches
B) 7 inches
C) 10 inches
D) 8 inches
192 divided by 24 equals 8, so the model measures 8 inches.
Part B: Fill in the Blank
Write the correct answer on each line.
1. A recipe uses flour, sugar, and butter in a 4:2:1 ratio. If 14 cups total are used, butter equals 2 cups.
14 divided by 7 is 2 per part, and butter is 1 part, so 2 cups.
2. On a map, 1 cm represents 25 km. Two towns are 6 cm apart on the map, so they are 150 km apart.
6 cm times 25 km per cm equals 150 actual kilometers.
3. Mixing concrete uses cement, sand, and gravel in 1:2:4. To make 21 buckets, you need 12 buckets of gravel.
21 divided by 7 is 3 per part, and gravel is 4 parts, totaling 12.
4. A scale drawing uses 1 inch = 8 feet. A room 32 feet long appears 4 inches on the drawing.
32 divided by 8 equals 4 inches on the scale drawing.
5. A juice mix has water, apple, and orange in 5:3:2. Out of 50 oz total, orange juice is 10 oz.
50 divided by 10 is 5 per part; orange has 2 parts, equaling 10.