There are a red, yellow, blue and green tennis balls respectively in a set. How many subsets of these balls can I get without using the green ball?	Choose one:
A) 9	B) 7	C) 8	D) 6	E) 10
This is a combination solution   Since we have 3 different kinds of Balls other than the green ball we can take any ball from the set of 3 to make a subset as follows.   381 +382 + 383 = 7   Plus the one set that is null that is the Set having no element in it which is 380 =1   = 7 + 1= 
<gadget id="calculator">7 + 1</gadget>
<output>8</output>
8   8= 8
<result>C</result>
There are a red, yellow, blue and green tennis balls respectively in a set. How many subsets of these balls can I get without using the green ball?