The probability of getting the same colour twice is approximately 34%.

Explanation:
Area is pi×r^2 and you times it by the fraction of the circle you have as its not a full circle.
You would have no problem at all if it said "7 cows minus 2 cows", or "7 books minus 2 books". The THINGS just happen to be m's instead of cows or books.
The answer is one hundred