Answer:

Step-by-step explanation:
The systems of equations are
Let us assume the rate of the current be c
Now actual speed against the current is (15 - c)
And, the actual speed with the current is (15 + c)
Here we applied the time formula i.e. distance by speed
Also the upstream time - downstream time = 4
Now the equations are

Volume = (l * w * h) or (11 * 3 * x) which will equal surface area. Volume is 33x for now
Surface Area = 2 (x * 11) + 2 (x * 3) + 2 (11 * 3)
Set Volume equal to surface area. I simplified SA already.
33x = 22x + 6x + 66
33x - 28x = 66
5x = 66
x = 66/5 or 13.2
I’m Not 100% Sure, But I Would Think 13.1% Is The Answer.
Answer:
read below
Step-by-step explanation:
A1: I think D because you have a medium average mix of concentrate that will mix with only 2 more cups than itself, so this would keep it fine. A could also work sooooo.... A or D. i dont know at this point. B COULD be a possible solution but it's 5 vs 9.
A2: C
1 cup of concentrate vs 2 water.... the water will make it MUCH more of a clear color.
Question C: this is more time consuming and I am tired so for you this might be easier if you're not as tired so based on what I'm reading you need to do math for each of the 4 options above, concentrate and water mix, and then divide the total of the 2 types of cups for every option.
Hope Q1 and Q2 helped though!