Jennie is making popcorn. The recipe calls for

cup of butter, 3
tablespoons of kernels, and 1 teaspoon of salt. If she uses 10
tablespoons of kernels, how much butter does she need? Round your
answer to the nearest hundredth.

1 answer

First, we need to determine the ratio of popcorn kernels to butter based on the original recipe.

The original recipe uses:

  • \(0.5\) cup of butter (which is equivalent to \(8\) tablespoons, since \(1\) cup = \(16\) tablespoons),
  • \(3\) tablespoons of kernels.

Now, we find the ratio of kernels to butter: \[ \text{Butter per tablespoon of kernels} = \frac{8 \text{ tablespoons of butter}}{3 \text{ tablespoons of kernels}} = \frac{8}{3} \text{ tablespoons of butter per tablespoon of kernels}. \]

Next, Jennie uses \(10\) tablespoons of kernels. To find the amount of butter she needs, we can multiply the number of tablespoons of kernels by the ratio we found: \[ \text{Butter needed} = 10 \text{ tablespoons of kernels} \times \frac{8}{3} \text{ tablespoons of butter per tablespoon of kernels}. \]

Calculating that: \[ \text{Butter needed} = 10 \times \frac{8}{3} = \frac{80}{3} \text{ tablespoons of butter} \approx 26.67 \text{ tablespoons of butter}. \]

Now, converting tablespoons back to cups (since \(1\) cup = \(16\) tablespoons): \[ \text{Butter in cups} = \frac{26.67 \text{ tablespoons}}{16} \approx 1.667 \text{ cups of butter}. \]

So the final answer, rounded to the nearest hundredth, is: \[ \text{Butter needed} \approx 1.67 \text{ cups}. \]