Answer: 100 concert tickets
Explanation:
Let "x" be the number of concert tickets the band must sell.
The cost per ticket is $7.50, and the local business donates an additional $0.50 for each $1.00 in ticket sales. So, for each ticket sold, the band receives $7.50 + $0.50 = $8.00.
To raise the rest of the money needed for the trip, they need to raise a total of $800.00 (as calculated earlier).
Now, we can set up an equation:
Total earnings from ticket sales = Number of tickets sold × Earnings per ticket
$8.00x = $800.00
To find the least number of tickets the band must sell, divide both sides of the equation by $8.00:
x = $800.00 / $8.00
x = 100
So, the band must sell at least 100 concert tickets to raise the rest of the money needed for the trip.