Answer:

Step-by-step explanation:
Let us first find the number of possible credit card numbers that can be formed with the numbers 0 - 9.
We want to form a 16 digit number out of 10 digits, so, we have:

There are
numbers that can be formed.
There are only 100 million valid numbers (
). Let the number of valid numbers be n.
Therefore, the probability of picking a number that is valid is:
P(valid) = n / N

Answer:
8.3
Step-by-step explanation:
I am going to go with the assumption that your equation is

. If there is only one solution, then the equation must be a perfect square. So square

to solve for the equation in the similar form that is given.

. So the variables match up perfectly in the equation, meaning that the value of m is 6, letter choice C.
Step-by-step explanation:
25÷5=5 so prime factors of 25 are 5×6