James takes a spinning class 3 times a week. He works out for 1.5 hours each class and burns 7 calories per minute. How many calories does he burn per week? Think carefully first, then make a decision:
He works out for 1.5 * 60 = 90 minutes per class. So he burns 90 * 7 = 630 calories per class. That means he burns 630 * 3 = 1890 calories per week. So, the answer is 1890.