Answer:
The amount of salads sold that day were 93.
Explanation:
Information to note:
Salad = $6.50
Drinks = $2.00
Total amount sold = 209
Total amount of money gained = $836.50
Set the system of equation. Let salad = s, and drinks = d
s + d = 209
6.50s + 2d = 836.50
Isolate the variable s in the first equation. Note the equal sign, what you do to one side, you do to the other. Subtract d from both sides:
s + d = 209
s + d (-d) = 209 (-d)
s = 209 - d
Plug in the new expression for s into the second equation:
s = 209 - d
6.50s + 2d = 836.50
6.50(209 - d) + 2d = 836.50
Simplify. Isolate the variable, d. First, distribute 6.50 to all terms within the parenthesis:
6.50(209 - d) = 1358.5 - 6.50d
1358.5 - 6.50d + 2d = 836.50
Simplify. Combine like terms:
1358.5 + (-6.50d + 2d) = 836.50
1358.5 - 4.50d = 836.50
Isolate the variable, d. Note the equal sign, what you do to one side, you do to the other.
Subtract 1358.5 from both sides:
1358.5 (-1358.5) - 4.50d = 836.50 (-1358.5)
-4.50d = 836.50 - 1358.50
-4.50d = -522
Isolate the variable, d. Divide -4.50 from both sides:
(-4.50d)/-4.50 = (-522)/-4.50
d = -522/-4.50
d = 116
The amount of drinks sold were 116.
Plug in 116 for d in one of the equations:
s + d = 209
s + (116) = 209
Isolate the variable, s. Subtract 116 from both sides:
s + 116 (-116) = 209 (-116)
s = 209 - 116
s = 93
The amount of salads sold that day were 93.
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