How many positive integers less than 90 are multiples of 6 but NOT multiples of 9?	Choose the correct choice from the following options:
A) 4 B) 6 C) 8 D) 10 E) 12
The LCM of 6 and 9 is 18.   If x &lt;90 and x is divisible by 6 not by 9 --&gt; x is NOT divisible by 18.   From 1--&gt; 90, we have 5 numbers which is divisible by 18: 18, 36, 54, 72, 90.   From 1--&gt;90, we have (90-6)/6 +1= 
<gadget id="calculator">(90-6)/6 +1</gadget>
<output>15</output>
15 numbers divisible by 6.   Therefore, our answer is 15-5= 
<gadget id="calculator">15-5</gadget>
<output>10</output>
10 numbers.   10
<result>D</result>
How many positive integers less than 90 are multiples of 6 but NOT multiples of 9?