Question

A coffee stand sells cups of coffee for $6 and cups of tea for $3 . Tuesday, a total of 75 cups were sold, and the total money collected was $312 . How many cups of coffee and how many cups of tea were sold?

Answer 1

c + t = 75......c = 75 - t
6c + 3t = 312

6(75 - t) + 3t = 312
450 - 6t + 3t = 312
-6t + 3t = 312 - 450
-3t = - 138
t = -138/-3
t = 46 <=== 46 cups of tea were sold

c = 75 - t
c = 75 - 46
c = 29 <=== 29 cups of coffee