Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-
Given : Sample size : n= 35 , large sample (n>30)
Mean difference : 
Standard deviation : 
Significance level : 
Critical value : 
Now, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students will be :-
Hence, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students =
Let
R = Ralph's age
S = Sara's age
First statement is translated as:
S = 3R
Second statement is translated as:
S + 4 = 2(R + 4)
Use the first equation to be substituted into the second one in terms of R which is the one we are actually going to solve for Ralph's age.
Since S = 3R, then
3R + 4 = 2(R + 4)
3R + 4 = 2R + 8
3R - 2R = 8 - 4
R = 4 years old
Yes the radius is 5. Is this a true or false question or is there something you forgot to add to it?
First, it depends how you want to solve the system. The easiest way is to solve by elimination. Eliminate the 2 s. Therefore, 4x = 8. Divide by 4 to find x. After dividing by 4, x=2. To find the y plug in 2 for x in the original equation. Try for the first one. 2 +2y =3. Subtract 2 from both sides of the equation. Then you get 2y =1. Divide by 2 in both sides and you get y = 1/2.
First we have to find the decimal equivalent by dividing.
5 / 8 = 0.625
It can't be an Integer because decimals can't be intergers, so that's ruled out
It can't be repeating as it does end, so that's also ruled out
Since the decimal does end it can't be non-terminating, non-repeating
So the answer is Terminating Decimal by process of elimination
