Answer:
The price of one pretzel is $-10.75
Explanation:
I'm not really sure why the pretzel would be negative dollars, but I checked my answer multiple times and it's right. For this problem you need a system of equations. The system will be 3d+2p=16 (since 3 drinks and 2 pretzels is 16 dollars) and 6d+5p=21.25 (since 6 drinks and 5 pretzels is 21.25 dollars). To solve this system, the first thing we're going to do is multiply the first system by -2 so that we can cancel the d variable. This will leave you with
-6d-4p=-32. Now, you can add this to the other equation. Since the -6 and 6 cancel, we only have the p variable now (that's why we multiplied by -2, to cancel out the d variable when we added later). Now we have -4p=-32 and 5p=21.25. Add these two equations together and you'll get 1p=-10.75, or p=-10.75. If you needed to solve for the drinks, you could plug -10.75 back into one of the first two equations, but for this problem we don't so -10.75 is your answer.