All numbers that only have one and itself as factors are prime. Therefore, to tell if a number is prime simply find it's factors. If it has more than two factors than it is not a prime number.
Answer:
50%
Step-by-step explanation:
There are 3 numbers fitting the rule, 1, 3, and 5. There is a 3/6 chance of picking one of them or 50%.
It is on sale for 50 percent so 320 is = 50 percent
100 percent = 640
You do both of those multiplied by each other