During three weeks, Bernie buys 3 * 2 = <<3*2=6>>6 chocolates.
In the local store, he pays for them 6 * 3 = $<<6*3=18>>18.
If Bernie would buy the same chocolates in the different store, he would pay 6 * 2 = $<<6*2=12>>12.
So Bernie would be able to save 18 - 12 = $<<18-12=6>>6.
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