In 48 days, they would have consumed 108 gallons, and have 22 left, so yeah. 48 days
I would tell her that her prediction is inaccurate because it isn’t guaranteed that the coin will land on both sides an equal amount of times. It’s possible that the coin could land heads up more often than it could land tails up or the other way around.
Here is a saying 5 and above give it a shove (round up) 4 and below go down low (round down). In your case you would leave it the same, because when rounding you would round to the nearest 10th.
Example:
54 would round down to 50 and 55 would be rounded up to 60.
Your answer is A !! go for it !!