Pls help- If a dilation has a rule (x, y) --> (2.5x , 2.5y) what is the scale factor?

Taking algebra two apex courses and need with these questions

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.

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?