Math

posted by .

Twenty tires are tested to see if they last as long as the manufacturer claims they do. Three tires fail the test. Two tires are selected at random without replacement for an inspection.
Find the probability that both tires fail the test.
Which is greater, the probability that the first tire fails and the second one passes? or vice-versa?

  • Math -

    p(f) = 3/20

    p(first) = 3/20 = .15
    p(second) = 2/19 = .105

    p first and second = .15 * .105 = .0158


    first fail, second pass
    = 3/20 * 18/19

    first pass second fail = 17/20 * 3/19

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math-statistics

    A manufacturer claims that the life span of its tires is 50,000 miles. You work for a consumer protection agency and you are testing this manufacturer's tires. Assume the life spans of the tires are normally distributed. You select …
  2. Physics

    I have to compare and contrast three types of tires, and relate them to physics. I've chosen: <li> Racing tires <li> Winter tires <li> All season tires I've chosen to compare them on: <li> Tire tread pattern …
  3. Prob and Stat

    A tire manufacturer guarantess that its tires will last for at least 60,000 miles. If the tire fails earlier, the manufacturer offers a prorated replacement. Too many such replacements are bad for business, so the manufacturer tests …
  4. math

    a tire manufacturer believes that the tread life of its tires are normally distributed and will lst an average of 60,000 miles with a standard deviation of 3,000 miles. sixty-four randomly selected tires were tested and the average …
  5. Probability and Statistics 2

    Bad Wheels Tire Company is interested in estimating the proportion of defective tires that it produces. The company tested a sample of 500 tires and found 16 to be defective. Find a 99% upper bound confidence interval for the true …
  6. Math - Probability

    You invent a new system to make excellent racing tires for the Indianapolis 500/ Your tires are good for an average of 105 miles, with a standard deviation of 7.5 miles. What is the probability that one of your tires can go for at …
  7. Math

    You invent a new system to make excellent racing tires for the Indianapolis 500/ Your tires are good for an average of 105 miles, with a standard deviation of 7.5 miles. What is the probability that one of your tires can go for at …
  8. statistics

    The tires are also tested for failure during a road test where they are subjected to road hazards. A test of 600 tires resulted in the failure of 30 tires. a) Find a 95% confidence interval on the proportion of failures for the new …
  9. Statistics

    Problem: you work for a manufacturer of tires (average life of your tires is 60.000 km with a standard deviation of 8.000 km). A supplier offers you new material that he says will increase by 10% the mileage of the tires you produce. …
  10. statistics

    twenty light bulbs are tested to see if they claims last long as the manufacturers claims they do. three light bulbs failed the test. two light bulbs are selected at random without replacement from this collection of bulbs find the …

More Similar Questions