In testing a certain kind of truck tire over rugged terrain, it is found that 25% of the trucks fail to complete the test run without a blowout. Of the next 15 trucks tested, find the probability that less than 4 have blowouts.

The probability that of 15 trucks, less than 4 trucks have blowouts is 0.4613.

Step-by-step explanation:

Let X = number of trucks having a blowout during the test run.

The probability of a truck having a blowout during the test run is, p = 0.25.

The sample of trucks selected is of size, n = 15.

The random variable X follows a Binomial distribution with parameters n = 15 and p = 0.25.

The probability mass function of X is:

Compute the probability that less than 4 trucks have blowouts as follows:

P (X < 4) = P (X = 0) + P (X = 1) + P (X = 2) + P (X = 3)

Thus, the probability that of 15 trucks, less than 4 trucks have blowouts is 0.4613.

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls

answer: 12   they all have at least 28 days

step-by-step explanation: haha