A. The ratio in this case is for every 40 minutes : one foot of water is leaked. If we start at 12 pm : 5 foot, next 12:40 pm : 4 foot, then 1 pm would have 3.5 feet. This is because for every 40 minutes is what caused one foot to leak but since we are at 12:40 adding 40 minutes would get us to 1:20 pm, not 1 pm. That means 20 minutes passed, half the time of 40 minutes meaning half the amount of one foot.
