Answer:
Step-by-step explanation:
Given : In a state where license plates contain six digits.
Probability of that a number is 9 =
[Since total digits = 10]
We assume that each digit of the license number is randomly selected .
Since each digit in the license plate is independent from the other and there is only two possible outcomes for given case (either 9 or not), so we can use Binomial.
Binomial probability formula: 
, where n= total trials , p = probability for each success.
Let x be the number of 9s in the license plate number.

Then, the probability that the license number of a randomly selected car has exactly two 9's will be :

Hence, the required probability = 0.098415
numerator = top part of the fraction
denominator = bottom part of the fraction
* means multiply
a.
you can only add the numerator when the denominator is the same
cant add the denominator
denominator has to be the same
1/5 = 4/20
4/20 + 7/20 = 11/20
b.
1 7/8 = 15/8
3/4 ÷ 15/8 =
3/4 * 8/15 =
24/60 = divide both top and bottom by 12 =
2/5
A=(7,3) b=(7,-2) c=(1,-2)