Question: If a car travels at a constant speed of 60 mph for 3 hours and then decreases its speed to 40 mph for the remaining distance, how long does it take to travel 300 miles?
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Q: What is the maximum value reached by the cosine function f(x) = cos(x) within the interval [0, π]?
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What is the standard deviation of the data set {10, 15, 20, 25, 30}?