Question

I have a red, blue, green, and yellow ball. If I put them all in a bag and pick one ball at a time (putting it back each time), what chance do I have of never picking a red ball, assuming I pick a color 40 times. Write as a decimal/percentage. (20 points! A good answer would be appreciated)

Answer 1

Explanation:

You have four balls

A draw of blue, green or yellow (3 balls) means success for NOT drawing a red ball

You have a 3 in 4 chance of not drawing a red ball on the first draw.

With replacement, the 3 in 4 chance occurs on every draw

the odds multiply together for each draw.

Chance of not drawing a red ball in 40 tries is (3/4)⁴⁰

or about 1 in 10⁻⁵ or 0.00001