3. C(8, r) = 28; r =​

Given:

To find:

The value of r.

Solution:

Combination formula:

We have,

Using the combination formula, we get

It can be written as:

Case 1:

And,

Case 2:

And,

Therefore, the value of r is either 2 or 6.

if the probability is 1/12, 75 people will receive a $25 gift card

step-by-step explanation:

the area of the rectangle is 35units^2.

step-by-step explanation:

graph it and find the distance.

it is a 5*7 rectangle.

therefore the area is 35units^2.