Answer:
x=12
Step-by-step explanation:
First you make sure x is on both sides of the equation. So you do 0.7x-5-0.2x=0.2x+1-0.2x. Which just simplifies to 0.5x-5=1. You make sure x is the only thing on that side of the equation so you do 0.5x-5+5=1+5 which simplifies to 0.5x=6. Multiply the equation times 2 to just have x. x=12. The value that makes true of x is 12.
C would be the answer I think
Answer:the cost of one child's ticket is $6
the cost of one adult ticket is $9
Step-by-step explanation:
Let x represent the cost of one child's ticket
Let y represent the cost of one adult ticket.
Tickets for a minor league baseball game for an adult and two children cost a total of $21. This means that
2x + y = 21 - - - - - - - - - - 1
The adult ticket is three dollars more than a child's ticket. This means that
y = x + 3
Substituting y = x + 3 into equation 1, it becomes
2x + x + 3 = 21
3x + 3 = 21
3x = 21 - 3 = 18
x = 18/3 = 6
y = x + 3 = 6 + 3
y = 9
Answer:
The 90% confidence interval for the mean nicotine content of this brand of cigarette is between 20.3 milligrams and 30.3 milligrams.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 9 - 1 = 8
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 8 degrees of freedom(y-axis) and a confidence level of
. So we have T = 1.8595
The margin of error is:
M = T*s = 1.8595*2.7 = 5
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 25.3 - 5 = 20.3 milligrams
The upper end of the interval is the sample mean added to M. So it is 25.3 + 5 = 30.3 milligrams.
The 90% confidence interval for the mean nicotine content of this brand of cigarette is between 20.3 milligrams and 30.3 milligrams.