There are 5 boxes numbered from 1 to 5. Either a red ball or a green ball will be placed in each box in such a way that at least 1 box contains a green ball and the boxes containing green balls are consecutively numbered. How many different ways can this be done?
Pick one:
A) 15 B) 17 C) 19 D) 21 E) 23
1 green ball: 5 ways   2 green balls: 4 ways   3 green balls: 3 ways   4 green balls: 2 ways   5 green balls: 1 way   The total number of ways is   5*6/2= 
<gadget id="calculator">  5*6/2</gadget>
<output>15</output>
15   The answer is 15.
<result>A</result>
There are 5 boxes numbered from 1 to 5. Either a red ball or a green ball will be placed in each box in such a way that at least 1 box contains a green ball and the boxes containing green balls are consecutively numbered. How many different ways can this be done?