Explanation:

First, let's find out how much Mike spent to get into the park. This would be

25% of 136 is what?

"Percent" or "%" means "out of 100" or "per 100", Therefore 25% can be written as $\frac{25}{100}$.

When dealing with percents the word "of" means "times" or "to multiply".

Finally, lets call the number we are looking for "n".

Putting this altogether we can write this equation and solve for $n$ while keeping the equation balanced:

n = 25/100 xx $136 n = 1/4 xx$136

n = $34 To find how much Mike has left we need to subtract$34 from $136: $136 - $34 =$102