Second and Final Probability question.

For this question, I tried it using , but It doesn't feel right. and I'm not getting the correct answer, I think I just need a push in the right direction on this one.

Quote:

The probability of exactly 4 out of 10 people having a red ticket at a charity ball is aproximately 0.2508. What is the probability, as a percentage, of a random person having a red ticket? Round your answer to the nearest percent. (HINT: Red or Not Red.)

Am I supposed to set and solve backwards? I tried plugging as P in the above formula and solving, but that was more of a wild shot.

I'm not sure where to go with this one. =/ Any help would be appreciated!