If I choose four cards from a standard -card deck, with replacement, what is the probability that I will end up with one card from each suit?
I like your enthusiasm but please do not override other people's answers when you have nothing of value to add.
Adding a final answer to a trivial calculation is definitely not valuable. It only allows the asker to do nothing at all.
If an answerer puts up a half done answer it is usually because we want the asker to learn and not just copy.
If you believe what is done is incorrect then by all means add your own answer.
Do not override teaching answers.