The problem asks:

Ruby frosted 8 cookies in 20 minutes. At this rate, how many cookies could she frost in 2 hours?

Solution:

First, convert 2 hours into minutes: $2 \, \text{hours} = 2 \times 60 = 120 \, \text{minutes}$

Next, calculate Ruby's rate of frosting cookies. She frosts 8 cookies in 20 minutes, so the rate is: $\frac{8 \, \text{cookies}}{20 \, \text{minutes}} = 0.4 \, \text{cookies per minute}$

Now, multiply this rate by the total time of 120 minutes: $0.4 \times 120 = 48 \, \text{cookies}$

Thus, Ruby can frost 48 cookies in 2 hours.

Would you like more details on this solution? Here are some related questions:

1. How would the answer change if Ruby could frost 10 cookies in 20 minutes?
2. If Ruby frosts cookies at a rate of 0.5 cookies per minute, how many can she frost in 1 hour?
3. What if Ruby took breaks and frosted only for 1.5 hours—how many cookies would she frost then?
4. How many minutes would Ruby need to frost 100 cookies at the same rate?
5. What is the general formula to find how many cookies Ruby can frost in x minutes?

Tip: Always double-check units (minutes, hours, etc.) to ensure consistency when calculating rates.