It doesn't matter how may guests you have. As long as cake price is lower, that is the cheapest to buy. Therefore the cake cost for 13.50 is the cheapest one.
y=1.5x+22 Substitute 35 for x: y=1.5(35)+22; x=74.5, which means the discount package is cheaper unless Brian gets 75 car washes. or d plz make Brainleist.