your answer to A should be a ratio. the answer is "5:2".
Your answer to B is correct.
for part (c), what fraction of the tips does melissa get? multiply this by the total tip amount to get the size of her share.
part (d) is a similar method to part (c).
part (e): the ratio is "5:2". you can multiply both sides of the ratio by any number, so this is the same as "2.5:1" which is the same as "25:10". now can you answer?