There are 32 balls which are red, blue or green. If 15 balls are green and the sum of red balls and green balls is less than 23, at most how many red balls are there?  Answers:
A) 4 B) 5 C) 6 D) 7 E) 8
r+g+b=32   g=15   r + g &lt; 23   =&gt; r + 15 &lt; 23   =&gt; r &lt; 8   =&gt; at most 7 red balls   ANSWER:7
<result>D</result>
There are 32 balls which are red, blue or green. If 15 balls are green and the sum of red balls and green balls is less than 23, at most how many red balls are there?