8th Grade Homework help?

Question

Problem: License Plates in a certain state contain 3 letters followed by 4 digits. Assume that all combinations are equally likely.

1. Find the number of possible license plates.

2. Find the probability of not being assigned a plate containing c or d.

3. Find the probability of receiving a plate containing no vowels (A,E.I,O,U).

Answer 1

1.  the number of plates is 26 x 26 x 26 x 10 x 10 x 10 x 10, I guess that's 175,760,000.

2.  Let's see, that means you have a 24 x 24 x 24 x 10^4 chance of getting a plate w/o c or d,  138,240,000 out of 175,760,000 of not getting c or d.  YoU NEED TO REDUCE THAT RATIO...

3.  Hmmm,

( 21 x 21 x 21 x 10^4)   out of 175,760,000

...I'll let you figure that one out.