You go to a sandwich shop and spend $12.36. You want to leave a 10% tip. What is the tip and what is your total cost?

what kind od sandwich  cost 12.36 and why would you leave a tip if it cost so much

also just add 12.36 plus 1.84

A] The least square estimation that models that data will be given as follows:
m(x-x1)=y-y1
where:
slope,m=(y-y1)/(x-x1)
m=(5.15-3.8)/(1997-1990)
m=0.193
taking 1978 as our x=0, 1990 will be x=12
thus the equation will be:
0.193(x-12)=y-3.8
0.193x-2.316=y-3.8
thus
y=0.193x+1.484

b]
The minimum wage in 2025 will be as follows:
x=2025-1978=47
thus plugging the values in the equation we get:
y=0.193(47)+1.484
y=10.555