Final answer:
To make 15 chocolate bars, the recipe requires 5 tablespoons of powdered sugar, as determined by setting up a proportion based on the given recipe ratio and solving it.
Step-by-step explanation:
To determine the amount of powdered sugar needed to make 15 chocolate bars, we use proportional reasoning. First, we establish that 1 2/3 tablespoons of powdered sugar are needed for 5 bars. To find the amount required for 15 bars, we set up a proportion:
5 bars / 1 2/3 tablespoons = 15 bars / x tablespoons
Cross multiply to solve for x:
(5)(x) = (1 2/3)(15)
Since 1 2/3 is equal to 5/3 when expressed as an improper fraction, the equation becomes:
5x = (5/3)(15)
5x = (5)(5)
x = 5 tablespoons
Therefore, you would need 5 tablespoons of powdered sugar to make 15 chocolate bars.