Let the cost of the soft drink = C then the price of the sandwich was 3.5 times as much = 3.5C
And
C + 3.5C = Total Cost
C + 3.5C = 9
4.5C = 9 divide both sides by 4.5
C = 9/4.5 = $2.00 for the soft drink
And 3.5C = 3.5(2.00) = $7.00 cost of the sandwich
Remember that percent means parts out of 100
x/100
discount is the decrease
so we divide the decrease by the original total and get
100/5775=0.0173
convert to fraction
0.0173/1
make bottom number 100
multiply by 100/100
1.73/100=1.73%
round
2%
Both millimeters and quarts are units for volume.
