Using the binomial distribution, it is found that there is a 0.857 = 85.7% probability that at least 2 of the rolls come up as a 3 or a 4.
For each die, there are only two possible outcomes, either a 3 or a 4 is rolled, or it is not. The result of a roll is independent of any other roll, hence, the <em>binomial distribution</em> is used to solve this question.
Binomial probability distribution
The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem:
- There are 9 rolls, hence
.
- Of the six sides, 2 are 3 or 4, hence

The desired probability is:

In which:

Then



Then:


0.857 = 85.7% probability that at least 2 of the rolls come up as a 3 or a 4.
For more on the binomial distribution, you can check brainly.com/question/24863377
3a + b = 54...when b = 9
3a + 9 = 54
3a = 54 - 9
3a = 45
a = 45/3
a = 15 <===
The numbers are being multiplied by 7
.5 • 7 = 3.5
3.5 • 7 = 24.5
24.5 • 7 = 171.5
etc
A) 38*(1-20%)*(1-10%)=27.36
b)38*(1-30%)=26.6
c)Because in question one when you take off the 10% it is 10% of the already off price but when you take off 30% it is taking off from the original price