Answer:
The student council needs to sell a minimum number of 107 tickets to reach their goal.
Explanation:
The student council needs to raise $400 with each ticket costing $4. As such, the number of tickets that need to be sold is
$400/$4 = 100
Easy, right?
But Hold On
The student council also spent $25 on decorations, so they need to make that back too. Thus, they need to sell an additional amount of tickets of
$25/$4 = 6.25
Since you can't sell 0.25 of a ticket though, round the answer up to 7.
So the overall total number of tickets that must be sold is 107.