Let me break this down for you.
The coat is now $24 (after the 25% sale from original price), what the questions is asking is simply is "25% of what number is 24?" since the original value is not given but 25% of "unknown" is given.
In other words what this means is 75% of x is 24.
Let x = original price
Simple equation:
0.75x = 24
x = 24/0.75 = 32
Longer way (if it makes you understand better):
x - 0.25x = 24
0.75x = 24
x = 24/0.75 = 32
Better now?