~Hello There!~
First find out the total number of marbles:
In this case it is 10
Keep this number in mind as it will be the denominator
The probability of getting a pink the first time would be:

Since it is replacement, there would still be 3 pink marbles for the second draw so this fraction would also be

You would need to multiply these results together to get the final result:

Doing this would give you an answer of:

Hope This Helps You!
Good Luck :)
Have A Great Day ^_^
- Hannah ❤