There are 7 boxes numbered from 1 to 7. 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? Choose the correct choice from the following choices.
A) 26  B) 28  C) 30  D) 32  E) 34
1 green ball: 7 ways   2 green balls: 6 ways   3 green balls: 5 ways   4 green balls: 4 ways   5 green balls: 3 ways   6 green balls: 2 ways   7 green balls: 1 way   The total number of ways is   7*8/2= 
<gadget id="calculator">  7*8/2</gadget>
<output>28</output>
28   The answer is 28.
<result>B</result>
There are 7 boxes numbered from 1 to 7. 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?