Birthday party planning

Cthulhu like to throw birthday parties for his goatty friends. Help him figure out how many invitations to send.

Your workbook should start off like this:

Start

The user fills in the age and friends cells, and clicks the button. The program shows the number of invitations. Like this:

Output

The number of invitations is the number of friends times two. (Each friend brings a pal.)

For goats 10 years old or older, the number of invitations must be at least 20. So if an old goat has 2 friends, change the number of invitations to 20.

Here's some more sample output.

Old goat, many friends

Old goat, few friends

Hint: nested if.

Upload your worksheet. The usual coding standards apply.

Where referenced