Question 1196358
.


Hey,  how your problem is worded,  it perplexes me . . . 


The correct wording is this:


<pre>
    How many 2-digit numbers can be written using the digits 5, 4, 6, 2, 8, 1, 7 if

      (a) repeating is allowed ?

      (b) repeating is not allowed ?
</pre>


To write correctly, &nbsp;read from good sources.


Or consider to hire somebody, who will edit your writing.