SOLUTION: Suppose you randomly choose a number between 1 and 100. What are the odds against choosing a prime number? Your computer password has 4 capital letters followed by 3 digits. You

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Question 387985: Suppose you randomly choose a number between 1 and 100. What are the odds against choosing a prime number?
Your computer password has 4 capital letters followed by 3 digits. Your friend randomly chooses 4 capital letters and 3 digits. Use a calculator to find the probability that your friend chooses your password.?
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
For the first problem you will just have to count the number of prime numbers between 1 and 100. (Remember that 1 is not considered prime or composite.) The probability will be the number of primes over the total number of possible numbers (100).

For the second problem, since it does not say that the 4 letters must be difference we must assume that repetitions are possible. And we must also assume that your friend gets only one guess.

The number of possible passwords would be:
26*26*26*26*10*10*10
The probability of your friend guessing your password in one guess:
1/26*26*26*26*10*10*10
(Use your calculator to simplify the denominator.)