Lizzy: Joe goes camping with his dad on a Friday. Joe's dad has 21 marshmallows, and Joe has four times as much marshmallows as his dad. If Joe’s dad roasts a third of his marshmallows, and Joe roasts half of his marshmallows, how many marshmallows did they roast in total?.
Me: Hmmm, let me think. I think this is the detailed solution:
Joe’s dad roasts 21 / 3 = 7 of his marshmallows. Joe has 21 * 4 = 84 marshmallows. Joe roasts 84 / 2 = 42 of his marshmallows. Joe and his dad roasted 7 + 42 = 49 marshmallows in total. Final answer: 49.