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.

Sandwiches = S
Water = W

S + W = 200
S +W -W = 200-W
S = 200-W

$3S + $0.75W = $318.75
$3(200-W) + $0.75W = $318.75
$600 - $3W + $0.75W = $318.75
$600 -$2.25W =  $318.75
$600 - $600 - $2.25W = $318.75 - $600
- $2.25W = -$281.25
-$2.25W/-$2.25 =  -$281.25/-$2.25
W = 125

S = 200-125
S = 75

Mikhael bought 75 sandwiches and 125 bottles of water

CHECK
$3S + $0.75W = $318.75
$3(75) + $0.75(125) = $318.75
$225 + $93.75 = $318.75
$318.75 = $318.75

It is blindness and randomization