When Kendra bought 2 toys, she paid 2*$20 = $<<2*20=40>>40
Since the price of a hat is $10, when Kendra bought 3 hats, she paid 3*$10 = $<<3*10=30>>30
The total costs for the hats and wooden toys Kendra bought is $40+$30 = $<<40+30=70>>70
From the $100 bill, Kendra received change worth $100-$70 =$<<100-70=30>>30
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