Question

I need help on this.

Banana Cupcakes
makes 10 cupcakes

1 cup granulated sugar

cup vegetable oil

1 large egg

4 tablespoons sour cream

2 medium-sized ripe bananas, mashed

1 cups all-purpose flour

1 teaspoon baking soda

teaspoon salt

1 teaspoon vanilla extract

pinch of nutmeg

You will use the recipe above to answer the following questions:

This recipe serves 10, but you need to serve 30. What number will you need to multiply the amount of each ingredient by to adjust the recipe? How did you determine this number?
How much vegetable oil do you need for 30 cupcakes?
How much flour do you need for 30 cupcakes?
What is the difference in the amount of vanilla extract you would need for 30 cupcakes?
What is the difference in the amount of salt you would need for 30 cupcakes?
In the real world, even though you make adjustments to a recipe to accommodate the number of people you need to serve, you sometimes round the amount of an ingredient instead of using an exact amount. Which ingredient would it make more sense to round rather than coming up with the exact amount? Why?

Answer 1

3, because if it only makes 10 cupcakes, you need to triple it (i.e. 10*3=30); (Assuming it was 1 cup oil) 3 cups vegetable oil; 3 cups flour; the difference is 2 teaspoons; (Assuming it was 1 teaspoon salt) the difference is 2 teaspoons; It would make sense to round the bananas because "medium-sized bananas" depends on your personal opinion, which means it's already rounded and further rounding wouldn't hurt as long as you're careful.

Answer 2

Here we have a recipe that works for 10 serves.

Then, if we want to make 30 servings, we need to use that recipe 3 times. (because x*10 = 30, then x = 30/10 = 3)

This would be equivalent to multiply each ingredient by 3.

for 30 cupcakes we need:

3 cups of vegetable oil.

3 cups of all-purpose flour

(because for each one of these ingredients we needed only 1 cup to make 10 cupcakes).

for 10 cupcakes we need 1 teaspoon of vanilla.

for 30 cupcakes we need 3 teaspoons of vanilla, the difference is 3 - 1 = 2.

So the difference is 2 teaspoons.

About which quantities we should round are those where we may have mixed numbers or big numbers.

For example, we have 4 tablespoons of sour cream for 10 servings, then for 30 servings we should have:

3*4 = 12 tablespoons.

We could round this down to 10 tablespoons.