Question 536428
1) getting none of them correct? 
(3/4)^5 = 243/1024
.
2) getting all of the questions correct? 
(1/4)^5 = 1/1024
.
3) getting at least one of the questions wrong?
1 - 1/1024 = 1023/1024
.
4) getting your first incorrect answer on the fourth question?
(1/4)^3 * 3/4 = 3/256
.
Ed