Average of A if column B is blank and C is populated unless containing specific text

Hello all,

I've had a look through the forum for the answer to this, but have not managed to locate it. If this has been asked in another post, please could you direct me to it.

I have created an example to demonstrate what I am trying to achieve (in plain text below and attached as an XLSX).

I am looking to work out the average of column A (Time) if the following criteria is matched:

1. Column B (Fruit) is blank AND
2. Column C (Colour) is populated, unless
a) Column C contains Green OR
b) Column C contains Yellow OR
c) Column D contains Large.

A B C D
1 TIME FRUIT COLOUR SIZE
2 6 APPLE GREEN LARGE
3 4 MEDIUM
4 9 ORANGE ORANGE SMALL
5 18 ORANGE SMALL
6 17 APPLE BLUE MEDIUM
7 11 ORANGE MEDIUM
8 23 GREEN SMALL
9 6 ORANGE SMALL
10 3 BLUE LARGE
11 7 BANANA MEDIUM


Using this example, only cells A5 and A9 meet the criteria specified, so the average should be 6.

In future, the amount of rows may change and additional colours added, so I would like my formula to handle these.

I am currently using Office 2007 but have access to any version.

Any help you can offer would be appreciated hugely.

Kind regards,
Matt

P.S. Sorry for the poor formatting of the plain text example - I will learn how to use the insert table function for next time!