Answer:
And using the probability mass function we got:
And replacing we got:

Step-by-step explanation:
Let X the random variable of interest "number of students graduated", on this case we now that:
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
We want to find the following probability:
And using the probability mass function we got:
And replacing we got:

Answer:
Ashley’s backpack is the better buy.
Step-by-step explanation:
You have to calculate the price that was paid for each backpack after the discount was applied.
Ashley’s backpack: $65*0.25= $16.25
Final price= $65-$16.25= $48.75
Robbin's backpack: $75*0.3= $22.5
Final price= $75-$22.5= $52.5
According to this, the backpack that is the better buy is the one that Ashley bought because after the discounts were applied it cost $48.75 and Robbin's backpack cost $52.2 which means that Ashley's backpack was cheaper.
The answer is 1/6.
With two dice, there are two possibilities to get 13. The first possibility is if dice 1 lands on 6 whilst dice 2 lands on 7. The second possibility is if dice 1 lands on 7 and dice 2 lands on 6. 2/12 simplifies to 1/6