GEOMETRY
posted by Anonymous on .
The squares of a 3×3 grid of unit squares are coloured randomly and independently so that each square gets one of 5 colours. Three points are then chosen uniformly at random from inside the grid. The probability that these points all have the same colours can be expressed as a/b, where a and b are coprime positive integers. What is the value of a+b?

Have you got the answer??
I'm so confused..
I don't know how to solve 
is it 458?

no not 458

so what's the answer?
give me the solution.. 
1528