The answer of the question which you asked above is
36^6x-6^5x=1
Sample space: H1, H2, H3, H4, T1, T2, T3, T4
All outcomes if the card is three: H3, T3
I was unclear about the last two parts of the question.
1,025. Multiply 55 by 15, then add the $200 fee. I hope this helps :)
9 years because if you do 4700 * 1.03= 4831 now do that 9 times you get 6,132.43