Let's denote the number of rides Daniel can go on as "r".
The admission to the fair is $4, and the cost of each ride is $1.50.
So, the total cost of the rides can be expressed as 1.50r.
Since Daniel had $25 to spend, we can write the inequality:
4 + 1.50r ≤ 25
This inequality represents that the sum of the admission fee ($4) and the cost of the rides (1.50r) should be less than or equal to $25.