Digits problem

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Source: — Problem Solving |

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by cramya » Mon Feb 16, 2009 5:24 pm
Even number ends wiht 0,2,4,6,8

First number cannot be 0 so 4 numbers to choose from. The rest 5 numbers to choose from.

4*5*5*5 = 500

I would choose C

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Re: Digits problem

by billzhao » Mon Feb 16, 2009 5:26 pm
jfranco23 wrote:How many 4-digit positive integers are there in which all 4 integers are even?

A. 625
B. 600
C. 500
D. 400
E. 256
I assume the question is: "How many 4-digit positive integers are there in which all 4 digits are even?"

There are 4 choices for the 1st digit: (2,4,6,8), 5 choices for the 2nd, 3rd and 4th digits: (0,2,4,6,8)

So there are 4*5^3 = 500 different integers

Answer is (C)
Yiliang