please help :(
1.A short multiple choice test has 4 questions. Each question has 5 choices, exactly one of which is correct. Willie has not studied for the test, so he guesses answers at random.
b.) calculate his probabilities of guessing 0,1,2,3 and 4 answers right.

I was given this formula: Pr(x)=nCx * Px (1-p) n-x

it would be a big help if someone helped me solve this. thankyou.

Question

please help :( 
1.A short multiple choice test has 4 questions. Each question has 5 choices, exactly one of which is correct. Willie has not studied for the test, so he guesses answers at random.
b.) calculate his probabilities of guessing 0,1,2,3 and 4 answers right.

I was given this formula: Pr(x)=nCx * Px (1-p) n-x
 
it would be a big help if someone helped me solve this. thankyou.