You are getting ready to move and have asked some friends to help. For lunch,
you buy the following sandwiches at the local deli for $30: six tuna sandwiches
and six turkey sandwiches. Later at night, everyone is hungry again and you
buy four tuna sandwiches and eight turkey sandwiches for $30.60. What is the
price of each sandwich?
+128475 6 tuna + 6 turkey = 30 divide through by 6 ⇒ 1 tuna + 1 turkey = 5 ⇒ 1 tuna = 5 - 1 turkey (1)
4 tuna + 8 turkey = 30.60 (2)
Sub (1) into (2)
4 ( 5 - 1 turkey) + 8 turkey = 30.60 simplify
20 - 4 turkey + 8 turkey = 30.60
4 turkey = 30.60 - 20
4 turkey = 10.60
turkey = 10.60 /4 = $2.65 = cost of a turkey
tuna - 5 - 2.65 = $2.35 = cost of a tuna
