Mark buys a used car for $12,000. The value of the car depreciates 10% per year from the time he bought the car. The value of Mark's car, V(t), can be represented by which of the following functions?
V(t) = –0.90t + 12,000
V(t) = –0.10t + 12,000
V(t) = 12,000(0.10)t
V(t) = 12,000(0.90)t

Titus works at a hotel. part of his job is to keep the complimentary pitcher of water at least half full and always with ice. when he starts his shift, the water level shows 4 gallons, or 128 cups of water. as the shift progresses, he records the level of the water every 10 minutes. after 2 hours, he uses a regression calculator to compute an equation for the decrease in water. his equation is w –0.414t + 129.549, where t is the number of minutes and w is the level of water. according to the equation, after about how many minutes would the water level be less than or equal to 64 cups?