Proportions

If a recipe for 4 servings requires 6 cups of flour, how many cups of flour are needed for 12 servings?

A map has a scale of 1 inch representing 20 miles. If two cities are 3 inches apart on the map, how many miles apart are they in reality?

Sally and Tom are comparing the amounts of ingredients they used to make cookies. Sally used 2 cups of sugar for every 5 cups of flour. Tom used 8 cups of sugar for every 20 cups of flour. Who used a larger proportion of sugar to flour?

In a class, the ratio of boys to girls is 3:4. If there are 21 boys in the class, how many girls are there?

A recipe for pancakes requires 2 eggs for every 1 cup of milk. If Alex wants to triple the recipe, how many cups of milk will he need if he uses 12 eggs?

A car travels 150 miles using 5 gallons of fuel. How many gallons of fuel are needed to travel 450 miles at the same rate?

A fruit salad recipe calls for 2 apples for every 3 oranges. If you want to make a batch using 12 oranges, how many apples will you need?

A school's ratio of teachers to students is 1:20. If the school has 400 students, how many teachers does it have?

If 4 bags of chips serve 8 people, how many bags of chips are needed to serve 32 people at the same serving rate?

A painter mixes 5 liters of white paint with 2 liters of blue paint to make a certain shade of light blue paint. How many liters of white paint are needed to mix with 8 liters of blue paint to maintain the same color ratio?