# probability about american households math problem

#### DINOCALC09

9/10 households in America have a car. Let X denote the number among 4 randomly selected households that have a car.

A. Calculate P(X=2)

B. Calculate P(X>=2)

C. Calculate P(X<2)

I am unsure of what each point is exactly asking. I know that P stands for probability. Could someone put the inequalities into words for me so that I understand this further?

#### nzmathman

A) is asking the probability X is exactly 2 and only 2.
B) is asking for the probability X is greater than or equal to 2, ie. X=2, 3 or 4.
C) is asking for the probability X is less than (but NOT including) 2, ie. X=0 or 1.

Use binomial distribution to find the probabilities.

#### DINOCALC09

A. = 0.0486

B. = 0.9963

C. = 0.0037

is this correct. i think i understand. thank you. very helpful

#### nzmathman

Yes - some quick use of my graphics calculator gives the same answers you have found. (Nod)