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:



⇒ 
Answer:
B. -1
Step-by-step explanation:
examples:
1 and -1
1/2 and -2
Answer:
2.5 cm
Step-by-step explanation:
We see the diameter is 5cm
so the radius is half the diameter
5/2 = 2.5 cm
Answer: 3:5
Step-by-step explanation:
33x-54y=6x+6y-3x-10y
33x-54y=3x-4y
30x=50y
3x=5y