For number 13 x=70 and y=115 hope this helped
Answer:
4
Step-by-step explanation:
Let 'a' be the number of ounces of 2%-solution in the 25-ounce mixture
and 'b' be the number of ounces of 5%-solution in the 25-ounce mixture.
Since, fluid ounces of each concentration should be combined to make 25 fl oz.
So, a+b=25 (Equation 1)
And, a container of 2% acid solution and a container of 5% acid solution should be combined to make 25 fl oz of 3.2% acid solution.
So, a of 2% + b of 5% = 3.2% of 25
![(a \times \frac{2}{100})+(b \times \frac{5}{100})= 25 \times \frac{3.2}{100}](https://tex.z-dn.net/?f=%20%28a%20%5Ctimes%20%5Cfrac%7B2%7D%7B100%7D%29%2B%28b%20%5Ctimes%20%5Cfrac%7B5%7D%7B100%7D%29%3D%2025%20%5Ctimes%20%5Cfrac%7B3.2%7D%7B100%7D%20)
![(0.02a)+(0.05b)= 0.8](https://tex.z-dn.net/?f=%20%280.02a%29%2B%280.05b%29%3D%200.8%20)
Multiplying the above equation by 100, we get
(Equation 2)
Substituting the value of a=25-b in equation 2, we get
![2(25-b)+5b=80](https://tex.z-dn.net/?f=%202%2825-b%29%2B5b%3D80%20)
![50-2b+5b=80](https://tex.z-dn.net/?f=%2050-2b%2B5b%3D80%20)
![50+3b=80](https://tex.z-dn.net/?f=%2050%2B3b%3D80%20)
![3b=30](https://tex.z-dn.net/?f=%203b%3D30%20)
![b=10](https://tex.z-dn.net/?f=%20b%3D10%20)
Since, a=25-b
a= 25-10
a=15.
So, 15 fluid ounces of 2% solution combined with 10 ounces of the 5% solution to create a 25-ounce mixture at 3.2% concentration of acid.
1 pound = 16 ounces
16 * 5.5 = 88 ounces per day
88*7 = 616 ounces per week
616 * 2 = 1232 ounces in 2 weeks