Missing Ball
John's teacher decided to give a prize to two of her 20 students. She placed 20 balls numbered from 1 to 20 in a box and then randomly assigned a distinct number from 1 to 20 to each student. She intends to draw at random 2 balls from this box and give a prize to the two lucky students.
She drew a ball, but the ball fell from her hand and got lost. Nobody knows what the number on this ball was. Then the teacher decided to proceed with the draw using the 19 remaining balls. What is the probability that John wins the prize?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
0 solutions
No explanations have been posted yet. Check back later!