L=s+4 bc lisa is 4 and we don't know who old is Sammy..
Answer:positive because the answer is 5.
Step-by-step explanation:
Let x represent the gallons of water that is 10% salt.
Let y represent the gallons of water that is 25% salt.
Now, write the system of equations:
x + y = 10
.10x +.25y = 0.20 • 10
1) To make the system easier to solve, multiply all the terms in .10x +.25y = 0.20(10) by 100 to make them integers.
10x + 25y = 20 • 10
10x + 25y = 200
2) Solve for x.
x + y = 10
x = 10 - y
3) Substitute x with 10 - y in the other equation.
10(10 - y) + 25y = 200
100 - 10y + 25y = 200
Combine like terms.
100 + 15y = 200
Subtract 100 from both sides.
15y = 100
y = 20/3 or 6 2/3
4) Now that we have the numerical value of y, solve for the value of x by substituting once more.
a) x + y = 10
x + 20/3 = 10 or x + 6 2/3 = 10 (either equation is fine)
x = 10/3 or x = 3 1/3
The manager should combine 3 1/3 (3.33) gallons of 10% salt water and 6 2/3 (6.67) gallons of 25% salt water.
5) Always check the answers to make sure.
a) x + y = 10
3 1/3 + 6 2/3 = 10
9 3/3 = 10
10 = 10
b) .10x +.25y = 0.20 • 10
.10(3 1/3) +.25(6 2/3) = 0.20 • 10
1/3 + 5/3 = 2
6/3 = 2
2 = 2
<span>The equation models this situation 10x+15y=980
Where x represents number of basic washes and y represents the number of ultimate washes.For total sales we want to add the two basic given data.Therefore basic wash and ultimate wash which is equal to total sales on that day.</span>
