To determine how long it will take to load 6 and 1/2 trucks, we first need to find out the loading time per truck based on the initial information.
If 3 and 1/2 trucks take 42 minutes, we can express this as:
3.5 trucks = 42 minutes
Now, we need to find the time taken per truck. We divide the total loading time by the number of trucks:
Loading time per truck = Total time / Number of trucks = 42 minutes / 3.5 trucks = 12 minutes per truck
Now that we know each truck takes 12 minutes to load, we can calculate the time taken to load 6 and 1/2 trucks:
6 and 1/2 trucks = 6.5 trucks
Time for loading 6.5 trucks = 12 minutes per truck × 6.5 trucks = 78 minutes
Therefore, it will take 78 minutes to load 6 and 1/2 trucks.