If there is 8 boys then there is 12 girls because 2x4=8 boys so 3x4=12 girls.
let's say the bill without the tip is "x" amount, so that'd be the 100% of the bill, but we also know that 4.50 is the 18% of "x".
so if 4.50 is the 18% of "x", how much is "x"?

Answer: The slope is -2/5 and the y-intercept is -1/3
There are 14 total cards and you need NOT yellow so it would be
8/14 which can be reduced to 4/7