Suppose that each student at a university has one of 4 expected graduation years and one of 21 majors. How many students must be enrolled to guarantee 2 graduations in the same year and major?

The correct answer is "168 students".

Step-by-step explanation:

According to the question,

Graduation probability,

Major probability,

Now,

The probability of having both graduation as well as major will be:

=

=

hence,

The number of students having guarantee two graduations throughout the same year and major will be:

⇒

By applying cross-multiplication, we get

⇒

⇒    

the answer is y = 11.54

hope this : )

b. y = 4x - 2

step-by-step explanation:

to find a parallel equation to an equation, make sure both equations have the same slope but different y-intercepts.

y = 4x + 1

4 = slope

1 = y-intercept

y = 4x - 2

4 = slope

-2 = y-intercept

they both have the same slope but different y-intercepts, so, b. is the correct answer.

and to check your work, you can graph both equations. : )