Answer:
Part A:




Part B:


and 
Step-by-step explanation:
Part A:
The inicial concentration of the lemonade is 50%, and the volume is 4 quarts, and we will add x quarts of a lemonade with a concentration of 100%, so the total volume will be y, and the concentration will be 0.7, so we have that:


Using the value of y from the first equation in the second one, we have:





Part B:
If he shoots a total of ten targets, we can write the equation:

Each stationary target is 2 points, and each moving target is 3 points, so if the total points is 23, we have:

If we subtract the second equation by two times the first one, we have:



⇒ 
If you subtract Betty's time for the swim, 27.948 seconds, from Nancy's time, 28.004 seconds, you will find that Betty was faster than Nancy by 0.056 seconds. She would be considered the winner of the 50-meter freestyle swim.
A obtuse isosceles b obtuse scalene c acute isosceles
D. X=18
Exp:
16-X=-2
-16 -16
-X=-18
X=18
Answer:
I would go with the second one.
Step-by-step explanation: