Please Help ASAP Combinations :(

10 freshmen, 10 sophomores, 8 juniors, and 7 seniors are eligible to be on a committee.

In how many ways can a dance committee of 17 students be chosen?

In how many ways can a dance committee be chosen if it is to consist of 5 freshmen, 4 sophomores, 6 juniors, and 2 seniors.

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?