The standard deviation is 2.2
since it has a diameter of 28, then its radius must be half that or 14.
X × x = x^2
x × -3 = -3x
3 × x = 3x
3 × -3 = -9
x^2 + 3x - 3x - 9
So I would agree with C because the -3x and the 3x cancel each other out. I hope this helps!
Answer:
We conclude that eighty percent of bike tires last at most 14.4 months.
Step-by-step explanation:
We know that a pair of bike tires can last 18 months if used every day.
We calculate how much eighty percent of the tire will last in months.
We have the following proportion:
We conclude that eighty percent of bike tires last at most 14.4 months.