Question 85108
How many different two-digit numbers can be formed from the digits 3, 1, 4, and 5 (allowing reuse)? 
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1st digit: 4 ways
2nd digit: 4 ways

How many different two-digit numbers can be formed from the digits 3, 1, 4, and 5 (allowing reuse)? 
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total ways 4*4 = 16
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Cheers,
Stan H.