Justin writes the letters i-l-l-i-n-o-s on cards and then places the cards in a hat. what are the odds against picking an i?

2/8 or 1/4 for picking it.
6/8 or 3/4 for not picking it.

We will need to make a ratio of the odds of a certain letter being picked to the total amount of letters in the hat.

We want to know what will the probability be if we don't pick an I
There are two I's. So, subtract that from the total amount of letters. 7 - 2 = 5
The total amount of letters is 7.

Now we have the ratio 5:7. You probably want a percentage so we will need to convert the ratio into a percent. To do this, divide the top by the bottom.

5 / 7 ≈ 0.714

To convert the decimal into a percent, simply move the decimal point to places to the right then convert the decimal point into a % sign.

0.714 = 71.4%

So, there will be 71.4% of not drawing an I from the hat.

EDIT:

I found a mistake in my answer.