Selina is selling some of her old clothes to a second-hand store. They will buy her pants for $5 each, her shorts for $3 each, and her shirts for $4 each. She sells 3 pairs of pants, 5 pairs of shorts, and some shirts. After she gets her money, she sees 2 shirts that she likes which cost $10 each and buys them. She leaves the store with $30. How many shirts did she sell to the store?
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