Sarah wants to buy snacks for her party. She buys 10 bags of chips and 15 bottles of soda. Each bag of chips costs $3, and each bottle of soda costs $2. She has a coupon that gives her a 20% discount on the total cost of the chips. Calculate the total amount Sarah needs to pay after applying the discount. Let's think step by step and output the final answer within \boxed{}.
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