Answer: a) $ 382.50 
Explanation:
Since, According to the question , He receives supplies for his pretzel business weekly. he usually works concession at three events a week and averages sales of 150 pretzels at each event.
Therefore, Total pretzels for a week = 

And, his each pretzel cost is $0.85
So, he need to budget weekly for his supplies = Total pretzels for a week×each pretzel cost = 

Therefore required answer is $ 382.50