The correct option is (C):
To determine the total number of trips made by the two trucks delivering 100 metric tons of gravel, let's analyze the statements:
- Statement A: "The smaller truck carried 5 metric tons of gravel on each trip to the site, and the larger truck carried 8 metric tons of gravel on each trip to the site."
From this statement, we can set up equations to find the number of trips made by each truck if we assume they deliver a certain total amount together.
- Statement B: "Each truck delivers the same total amount of gravel to the site."
This statement indicates that both trucks deliver the same quantity of gravel, but it doesn't provide specific information on how much each truck carries per trip.
Now, let's combine both statements:
From Statement A, if we let \( x \) be the number of trips made by the smaller truck and \( y \) be the number of trips made by the larger truck, we have:
\[5x + 8y = 100\]
From Statement B, we know that the total gravel delivered by each truck is the same, which means:
\[5x = 8y\]
Using both statements, we can solve for \( x \) and \( y \) to find the total number of trips.
Thus, the question can be answered using both statements together but not with either statement alone.
The correct option is C: If the question can be answered with the help of both statements together but not with the help of either statement alone.