Ratios and Proportions Flashcards

A runner completes 5 laps in 8 minutes. At this rate, how many laps can she complete in 24 minutes?

Answer: 15 laps

5/8 = x/24, so x = (5 × 24) / 8 = 15 laps.

A recipe makes 48 cookies using 3 cups of sugar. How many cups of sugar are needed to make 80 cookies?

Answer: 5 cups

3/48 = x/80 gives x = (3 × 80) / 48 = 5 cups.

A gear with 24 teeth turns 3 times for every 2 turns of a gear with 36 teeth. If the larger gear turns 10 times, how many times does the smaller gear turn?

Answer: 15 times

The ratio is 3:2, so 3/2 = x/10 gives x = 15 turns.

On a scale drawing, 2 cm represents 5 meters. If a wall is 17.5 meters long, how long is it on the drawing?

Answer: 7 cm

2/5 = x/17.5 gives x = (2 × 17.5) / 5 = 7 cm.

If the ratio of wins to losses for a team is 7:3, and they played 60 games, how many games did they win?

Answer: 42 games

Wins are 7/10 of total games: (7/10) × 60 = 42.

Two quantities are in proportion if they change at the same rate. Which pair of values is NOT proportional to 4:10?

Answer: 10:22

4:10 = 2:5; 10:22 simplifies to 5:11, which is not equal to 2:5.

A car uses 2 gallons of gas for every 54 miles driven. How many gallons are needed for a 270-mile trip?

Answer: 10 gallons

2/54 = x/270 gives x = (2 × 270) / 54 = 10 gallons.