Let's denote the original cost of the meal as x.
The tip is 25% of the original meal cost, so the tip amount is 0.25x.
The total cost of the meal, including the tip, is the sum of the original cost and the tip amount:
Total cost = Original cost + Tip amount
25 = x + 0.25x
Combine like terms on the right side:
25 = 1.25x
Now, solve for x:
x = 25/1.25 = 20
Therefore the cost of the meal before the tip was $20.