Identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster. a large company wants to administer a satisfaction survey to its current customers. using their customer database, the company randomly selects 40customers and asks them about their level of satisfaction with the company. what type of sampling is used

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?