The value of x is
-4x + 8 = 42
-4x = 42 -8
-4x = 34
x = -8,5
Answer:
0.0158 = 1.58% probability that all of them are under 18.
Step-by-step explanation:
Probability of independent events:
If three events, A, B and C are independent, the probability of all happening is the multiplication of the probabilities of each happening, that is:

The percentage of people under the age of 18 was 23.5% in New York City, 25.8% in Chicago, and 26% in Los Angeles.
This means that 
If one person is selected from each city, what is the probability that all of them are under 18?
Since the three people are independent:

0.0158 = 1.58% probability that all of them are under 18.
Answer: 267.
Step-by-step explanation:
When there is no prior information for the population proportion, then the formula we use to find the sample size to estimate the confidence interval :
, where z* = Critical z-value and E + amrgin of error.
Let p = proportion of packages of ground beef sold at a particular store that have an actual fat content exceeding the fat content stated on the label.
Since , we have no prior information about p. so we use above formula
with E = 0.06 and critical value for 95% confidence =z* =1.96 [By z-table ] , we get

Hence, the required sample size is 267.
40 I believe because the space of the auto mobile catching up to the train is 4 hours. 4 times 30 is 120 miles so u need to figure out a number that can reach 120 in three hours. 3 times 40 is 120