Question

on Monday Joe bought 10 cups of coffee and doughnutsts for his office at the cost of $16.50.it turns out doughnuts were more popular than the coffee. on Tuesday he bought 5 cups of coffee and 10 doughnuts for a total of $14.25 how much was each cup of coffee

Answer 1

Coffee=C
Doughnuts=D

10c+5d=16.50
-2(5c+10d=14.25)

10c+5d=16.59
-10c-20=-28.50 (the 10c cancel out)
____________
-15d/-15=-12/-15

D=$.80

5c+10(.8)=14.25
5c+8=14.25
5c=6.25

c=$1.25