Confusing Word Problem

Here is a word problem that i found extremely hard to solve:

On a spelling test of 25 words, Patrick spelled 17 more words correctly than he spelled incorrectly. What percent of the words did he spell incorrectly?

First, i made a list of variables:

T: Total
R: Right
W: Wrong

I also wrote down: T=R+W and W=(R-17)

My first step was:

T=R+(R-17)

2nd:

T= 2R-17

Since thats the total, the fraction has to be:

R-17/2R-17

But i think the teacher expects a number so, can someone tell me what to to or give me a push in the right direction? Thanks alot!

As was noted elsewhere, further information was needed (from your original statement of the question) to obtain a numerical answer. Now that you have that additional information, plug it into the set-up (copied in your post) given by the other tutor.

Eliz.

We have Total = 25

Right + Wrong = 25
and
Right = Wrong + 17

So that gives us

Wrong + Wrong + 17 = 25

2w = 25-17 = 8

W = 4
and therefore R=21

So % of words spelled correctly = 21/25 = 80%

thanks! I knew i forgot a part! I guess algebra 1 isnt coming back to me that well.