CD Player Shopping

  The Greenes are buying a new CD player. Three stores have the model they want on sale this week. Here are the ads:
 Radio Shack: Regular Price=$200, Discount=20% off
Walmart: Regular Price=$180, Discount=30% off
Rex's: Regular Price=$210, Discount=10% off and Extra 20% off

Which store will give the Greenes the best buy and what will the price be?

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