7 1/2 /(4 1/2 - 5 1/8)

First, we need to simplify the denominator:

4 1/2 - 5 1/8 = (8/2 + 1/2) - (8/8 + 1/8)
= 9/2 - 9/8

To subtract these fractions, we need a common denominator:

9/2 - 9/8 = 36/8 - 9/8
= 27/8

Now we can substitute this value back into the original expression:

7 1/2 / (4 1/2 - 5 1/8) = 7 1/2 / (9/2 - 9/8)
= 15/2 / (9/2 - 9/8)
= 15/2 / (27/8)

To divide fractions, we flip the denominator and multiply:

15/2 / (27/8) = 15/2 * (8/27)
= 2.222... (rounded to three decimal places)

Therefore, the answer is approximately 2.222.