Your recipe for potatoes calls for 15 lb of peeled potatoes and yields 50 portions, each weighing 5 oz. How many pounds of peeled potatoes do you need to serve thirty 3-ounce portions during the dinner service?

Thus To serve thirty 3-ounce portions, 5.625 pounds of peeled potatoes are required. This involves converting 90 ounces (30 portions *3 ounces each) to pounds by dividing by the conversion factor of 16 ounces per pound.

The student's question involves the conversion of units and calculation of quantities for a recipe, which falls under the subject of Mathematics. Specifically, it's a problem of proportional reasoning and unit conversion typically covered in high school level mathematics.

Step-by-Step Solution

To solve this question, two conversions need to be made:

Converting pounds to ounces to make sure both units are consistent.

Determining the amount of peeled potatoes required for thirty 3-ounce portions.

Unit Conversion: Since 1 pound = 16 ounces, we first convert the required number of pounds of potatoes to ounces. For thirty 3-ounce portions, the total required is 30 portions imes 3 ounces/portion = 90 ounces.

Determining Required Amount: We then convert ounces back to pounds to determine the final result. We have a total of 90 ounces, and we need to convert this back to pounds, so 90 ounces \/ 16 ounces/pound = 5.625 pounds of potatoes.

Original Recipe

The recipe mentioned in the question yields 50 portions of 5 ounces each. Therefore, the total amount of potatoes used in the original recipe is 50 portions * 5 ounces/portion = 250 ounces, which is equivalent to 250 ounces \/ 16 ounces/pound = 15.625 pounds of potatoes.