A school canteen sells a sandwich at $2, a hamburger at $2, one stick of hotdog at $1, and a can of fruit juice at $2 each can. Selene buys three sandwiches and a can of fruit juice. Tanya buys two hamburgers and two cans of fruit juice.  How much do Selene and Tanya spend together?
Please reason step by step, and put your final answer within \boxed{}.
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