Answer:
10
Step-by-step explanation:
We will use a system of equations to solve this. We do not know how much of the 25% bleach solution is used; we will use x to represent this. We know that 5 cups of the 10% solution was used. We do not know how much of the resulting solution we have; we will use y to represent this. This gives us the equation
x+5 = y
Using the decimal forms of the percentages for each solution, we have 0.25x (25% solution for x cups), 0.1(5) (10% solution for 5 cups) and 0.2y (20% solution for y cups); this gives us the equation
0.25x+0.1(5) = 0.2y
This gives us the system
![\left \{ {{x+5=y} \atop {0.25x+0.1(5)=0.2y}} \right.](https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7Bx%2B5%3Dy%7D%20%5Catop%20%7B0.25x%2B0.1%285%29%3D0.2y%7D%7D%20%5Cright.)
To use elimination, we will make the coefficients of x the same by multiplying the top equation by 0.25:
![\left \{ {{0.25(x+5=y)} \atop {0.25x+0.5=0.2y}} \right. \\\\\left \{ {{0.25x+1.25=0.25y} \atop {0.25x+0.5=0.2y}} \right.](https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7B0.25%28x%2B5%3Dy%29%7D%20%5Catop%20%7B0.25x%2B0.5%3D0.2y%7D%7D%20%5Cright.%20%5C%5C%5C%5C%5Cleft%20%5C%7B%20%7B%7B0.25x%2B1.25%3D0.25y%7D%20%5Catop%20%7B0.25x%2B0.5%3D0.2y%7D%7D%20%5Cright.)
We will now subtract the second equation from the first:
![\left \{ {{0.25x+1.25=0.25y} \atop {-(0.25x+0.5=0.2y)}} \right. \\\\0.75 = 0.05y](https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7B0.25x%2B1.25%3D0.25y%7D%20%5Catop%20%7B-%280.25x%2B0.5%3D0.2y%29%7D%7D%20%5Cright.%20%5C%5C%5C%5C0.75%20%3D%200.05y)
Divide both sides by 0.05:
0.75/0.05 = 0.05y/0.05
15 = y
There were 15 cups of the resulting 20% solution. Substituting this into the first equation, we have
x+5=15
Subtract 5 from each side:
x+5-5=15-5
x = 10
60 x 0.25 = 15
Your dog lost 15 pounds
Answer:
x > 48/5 the first one is false
Answer:
D. ![-y > 10](https://tex.z-dn.net/?f=-y%20%3E%2010)
Step-by-step explanation:
First, move the variable (+ 2y) to the left-hand side and change its sign.
![y - 2y - 7 > 3](https://tex.z-dn.net/?f=y%20-%202y%20-%207%20%3E%203)
Then, move the constant (+ 7) to the right-hand side and change its sign.
![y - 2y > 3 + 7](https://tex.z-dn.net/?f=y%20-%202y%20%3E%203%20%2B%207)
Then, collect the like terms (y - 2y)
![-y > 3 + 7](https://tex.z-dn.net/?f=-y%20%3E%203%20%2B%207)
Finally, add the numbers (3 + 7). That will get you your final answer.
![-y > 10](https://tex.z-dn.net/?f=-y%20%3E%2010)