Ticket-sale reveue for:
Thursday night: 200*40=8,000
Friday night: 240*50=12,000
Saturday afternoon: 220*40=8,800
Saturday night: 300*50=15,000

Maximum: 15,000
Minimum: 8,000

As a result, the difference between the maximum and the minimum ticket-sale revenue is: 15,000-8,000=7,000

The correct answer is D.

This question can be made simpler by considering that Thursday night's ticket price and number of tickets sold is the lowest of all four days, and vice versa for Saturday night.

So that means the minimum revenue has to be for Thursday night, i.e. $8,000, and highest for Saturday night, i.e. $15,000. Then calculations are as per everyone else'.

It's just good to be able to remove two potential calculations out of the equation early on, saves on time.
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The wording "single performance" causes confusion here.

Solution :

$40 * 200 = 8000 <- Min
$50 * 240 = 12000
$40 * 220 = 8800
$50 * 300 = 15000 <- Max

15,000 - 8000 = 7,000

Hence D.