Answer:
At least 55 tickets must be sold to cover the remaining cost of the party.
Step-by-step explanation:
Total money needed for the party  = $350
The money already with the committee  = $75
Now, the money yet to be collected = Total Party Budget - Money present
                               = $350  = $75  = $275
Now, the cost of 1 ticket  = $5
Let us assume the number of tickets sold to cover the cost of party = m
⇒ The cost of m tickets  = 5 m
The renaming cost = Total cost of m tickets
or, 5 m = Â $275
⇒ m = 275/5  = 55
or, m = 55
Hence, at least 55 tickets must be sold to cover the remaining cost of the
party by Josef.