Emily spent X dollars on Friday, twice that amount on Saturday, and then three times X on Sunday. Over the three days, she spent $120. What is the value of X, in dollars? Give me reasons, before answering the question
She spent X dollars on Friday. She spent 2X dollars on Saturday. She spent 3X dollars on Sunday. X + 2X + 3X = 120. 6X = 120. X = 20. So the final answer is 20.