A National Park Service survey of visitors to the Rocky Mountain region revealed that 50% visit Yellowstone Park, 40% visit the Tetons, and 35% visit both. 8. What is the probability a vacationer will visit at least one of these attractions

0.55 or 55%

Step-by-step explanation:

Let A represent the event when a vacationer visits Yellowstone Park

Let B be represent the event where a vacationer visits the Tetons.

We are told that 50% visit Yellowstone Park. Thus; P(A) = 50% = 0.5

Also,that 40% visit the Tetons. Thus;

P(B) = 40% = 0.4

Also that 35% visit both.

Thus; P(A & B) = 0.35

Now, probability that they visit at least one of these attractions will be P(A or B)

Now, formula for P(A or B) is;

P(A or B) = P(A) + P(B) - P(A & B)

Thus;

P(A or B) = 0.5 + 0.4 - 0.35

P(A or B) = 0.55

step-by-step explanation: 4 cause 2+2=4

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.