Lizzy: Annie goes to school. Today is her birthday, so Annie decided to buy some sweets for her colleagues. Every classmate got 2 candies. In the end, Annie got left with 12 candies. If there are 35 people in Annie's class in total, how much did Annie spend on candies, if one candy costs $0.1?.
Me: Hmmm, let me think. I think this is the detailed solution:
There are 35 people in Annie's class, which means, she has 35 - 1 = 34 classmates. Every classmate got 2 candies, so in total Annie gave out 34 * 2 = 68 candies. In the beginning she had 68 + 12 = 80 candies. One candy costs $0.1, so Annie spend 80 * 0.1 = $8 on candies. Final answer: 8.