high school math ratio problems

1 answer

Sure! Here are some high school math ratio problems along with their solutions:

Problem 1: Ratio of Ages

Sophia is 12 years old and her brother, Ethan, is 8 years old. What is the ratio of their ages, and what will the ratio be in 5 years?

Solution: Current age ratio of Sophia to Ethan: \[ \text{Ratio} = \frac{Sophia's , age}{Ethan's , age} = \frac{12}{8} = \frac{3}{2} \]

In 5 years, Sophia will be 17 and Ethan will be 13: \[ \text{New Ratio} = \frac{17}{13} \]

Problem 2: Mixing Paint

A painter mixes red and blue paint in the ratio of 4:3. If the painter wants to make 21 liters of paint, how many liters of red and blue paint should he use?

Solution: Let the amount of red paint be \( 4x \) and blue paint be \( 3x \). So, \[ 4x + 3x = 21 \] \[ 7x = 21 \quad \Rightarrow \quad x = 3 \] Then,

  • Red paint: \( 4x = 4 \times 3 = 12 \) liters
  • Blue paint: \( 3x = 3 \times 3 = 9 \) liters

Problem 3: Ratio of Distances

A car travels 120 miles in 2 hours while a bike travels 30 miles in 1 hour. What is the ratio of the distance traveled by the car to the bike?

Solution: Car's distance = 120 miles
Bike's distance = 30 miles
Ratio of distances: \[ \text{Ratio} = \frac{120}{30} = 4:1 \]

Problem 4: Sharing Money

Alice and Bob have a combined total of $180. If Alice has three times as much money as Bob, how much money does each person have?

Solution: Let Bob's amount be \( x \). Then Alice's amount is \( 3x \). \[ x + 3x = 180 \] \[ 4x = 180 \quad \Rightarrow \quad x = 45 \] So, Bob has $45, and Alice has: \[ 3x = 3 \times 45 = 135 \]

Problem 5: Ratio of Speeds

Two runners are racing. Runner A runs at a speed of 10 km/h while Runner B runs at a speed of 15 km/h. What is the ratio of their speeds?

Solution: Ratio of speeds: \[ \text{Ratio} = \frac{10}{15} = \frac{2}{3} \]

Problem 6: Recipe Adjustment

A recipe calls for 2 cups of sugar for every 3 cups of flour. If you want to use 9 cups of flour, how many cups of sugar do you need?

Solution: The ratio of sugar to flour is \( \frac{2}{3} \).
Let the cups of sugar be \( x \): \[ \frac{x}{9} = \frac{2}{3} \] Cross-multiplying gives: \[ 3x = 18 \quad \Rightarrow \quad x = 6 \] You need 6 cups of sugar.

Feel free to ask for more problems or explanations on a specific topic!