2. No. Read what it says; X1+X2 is the sum of two independent random variables. You are finding the probability that first success for X1 plus X2 is greater than 3.

4. Same as above.

5. No. I'm sure you have notes on the mean of a geometric random variable. Those "individual" means don't make any sense whatsoever, which should be the first clue that something is wrong.