Mikhael bought refreshments. sandwiches were $3 each and bottles of water were $0.75 each. he spent $318.75 on a total of 200 items. write how many sandwiches and how many bottles of water mikhael bought. can someone convert this to a system of equations

X= sandwiches
y= bottles of water

QUANTITY EQUATION
x+y= 200

COST EQUATION
$3x + $0.75y= $318.75

STEP 1
solve for one variable in quantity equation and substitute in cost equation

x+y= 200
subtract y from both sides
x= 200-y

STEP 2
substitute 200-y in for x

$3x + $0.75y= $318.75
3(200-y) + 0.75y= 318.75
600 - 3y + 0.75y= 318.75
combine like terms
600 - 2.25y= 318.75
-2.25y= -281.25
divide both sides by -2.25
y= 125 number of water bottles

STEP 3
substitute y=125 in either equation

x+y= 200
x + 125= 200
x= 75 sandwiches

ANSWER: There were 75 sandwiches and 125 bottles of water.

Hope this helps! :)