Answer: 49/100
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Explanation:
There are 7 dimes and 3 pennies, leading to 7+3 = 10 coins total.
The probability of not picking a penny is 7/10. If the first coin is put back, then the probability doesn't change for the second selection.
The probability of getting two dimes is (7/10)*(7/10) = 49/100 when the first coin is replaced.
If the first coin is not replaced, then the answer would be (7/10)*(6/9) = 42/90 = 7/15
