The Goal: Find Marco's average rate in hot dogs per hour.
Let:
RL = Leo's average rate (hot dogs/hour)
RM = Marco's average rate (hot dogs/hour)
T = Time spent competing (in hours)
From the problem statement:
Leo ate 36 hot dogs. So, RL = 36/T
Marco ate 30 hot dogs. So, RM = 30/T
We need to find the numerical value of RM
This means we need to find the value of T.
Analyzing Statement (1): Marco’s average rate was 6 hot dogs per hour less than Leo’s.
This can be written as an equation:
RM = RL − 6
Substitute the rate expressions in terms of T:
30/T = 36/T −6
Now, we can solve for T:
6= 36/T − 30/T
6= 6/T
6T=6
T=1 hour
Since we found T = 1 hour, we can now find Marco's average rate:
RM = 30/T = 30/1 =30 hot dogs per hour.
Since we can determine Marco's average rate, Statement (1) is SUFFICIENT.
Analyzing Statement (2): In the first 20 minutes, Leo ate 12 hot dogs.
First, convert 20 minutes to hours: 20 minutes = 20/60 hours = 1/3 hour.
This statement tells us Leo's rate during the first 20 minutes.
Leo's rate in the first 20 minutes =
12 hot dogs / {1/3 hour} =12×3=36 hot dogs per hour.
However, the problem states Leo ate 36 hot dogs during the entire competition. It does not state that Leo maintained a constant rate throughout the entire competition. It only states his overall average rate for the total time T was 36 hot dogs. His average rate for the first 20 minutes might be different from his average rate for the total time T.
If Leo's overall average rate (RL ) for time T was 36 hot dogs/hour, then T would be 1 hour (36/1=36).
If T=1 hour, then RM =30/1=30 hot dogs/hour. But this is an assumption that Leo's rate in the first 20 minutes is his overall average rate.
The question explicitly defines Leo's average rate as (total hot dogs) / (total time). Statement (2) provides an average rate for a portion of the time. We cannot assume that the rate in the first 20 minutes is the same as the rate for the entire contest unless specified. The problem says "Leo ate 36 hot dogs" (total) and "Marco ate 30 hot dogs" (total), and "competed for the same amount of time" (T). It does not say Leo's rate was constant.
Therefore, we cannot determine T from this statement alone. Statement (2) is NOT SUFFICIENT.
Conclusion:
Statement (1) alone is sufficient to answer the question.
The final answer is A