a. 7.5
b. 5
c. 2.5
sorry if it is in correct
30 divided by 4 = 7.5
10 divided by 2 = 5
7.5-5=2.5
Hey!
We know that if we see a number that apparently doesn't have a denominator, we can plug a "1" as a denominator because it's a whole number, for example, we could write.

Finding the inverse would be taking the reciprocal of it, that implies switching the fractions, the signs would change too, so, this would mean that the reciprocal of

would be,

Using Math, we can verify this is correct. To do that, we would have to use exponents.

Thanks!
-TetraFish
39% as a ratio would be 39:100. Since percents are over of a hundred it would be 39:100 or 39/100.