There are 52 white keys and 36 black keys on a standard piano. what is the probability that if a person did not look and hit the keyboard twice that he or she would first hit a white key and then hit a black key?

A) if $50000 is invested in a bank account that pays 9.3% of interest compounded on a six-monthly basis, how much money will be in the account after 3 and 12 years? b) if matusalen's father had put $2.0 in the bank when he was born and there, how long would matusalen have had to his death (969 years later) if the interest was 7% per year composed each month and weekly?