In a fruit salad, there are raspberries, green grapes, and red grapes. There are seven more than 3 times the number of red grapes as green grapes. There are 5 less raspberries than green grapes. If there are 102 pieces of fruit in the salad, how many red grapes are in the salad?
Please reason step by step, and put your final answer within \boxed{}.
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