Find the rate of change, (y2-y1)/(x2-x1), from the data given...
(2.16-1.26)/(12-7)=0.18
(1.26-0.72)/(7-4)=0.18
Since the rate is constant, this is a linear equation of the form y=mx+b. Furthermore, since 0 pencils cost 0, b=0, so the cost of the pencils is simply the number of pencils times 18 cents...
c(p)=0.18p (cost with respect to pencils is 0.18 times the number of pencils)
Answer:
The mean of the combined math and verbal scores is 1100, while the standard deviation is 141.
Step-by-step explanation:
Normal variables
Normal variables have mean
and standard deviation 
When we add normal variables, the combined mean is the sum of both means, and the standard deviation is the square root of the sum of both variances. The distribution is still normal.
In this question:
Verbal:
.
Math: 
Combined:


The mean of the combined math and verbal scores is 1100, while the standard deviation is 141.
12. I’m sorry I’m horrible at word problems
13. C
14. C