Question 1195198
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Consider the numbers 0,2,5,6. How many two-digit numbers can be formed without repetition, such that.
a) all are even?
b) all are greater than 60?
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            (a)   all are even ?



<pre>
Even number must have last digit 0, or 2, or 6.


If the last digit is 0, then the first digit can be any of 2, 5, 6.  It gives 3 numbers.

If the last digit is 2, then the first digit can be 5 or 6, giving 2 numbers.

If the last digit is 6, then the first digit can be 2 or 5, giving 2 numbers.


In all, there are  3 + 2 + 2 = 7  two-digit even numbers of this kind.
</pre>


&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) &nbsp;&nbsp;all are greater than &nbsp;60 ?



<pre>
There are only two such numbers. They are 62 and 65.
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Solved.