John buys thank you cards. He decides to buy them for people who got him Christmas and birthday presents. He sent 20 for Christmas gifts and 15 for birthday gifts. If each card cost $2 how much did he spend on cards? Give me reasons, before answering the question

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
He bought 20 + 15 = 35 cards. So he spent 35 * 2 = $70. So the final answer is 70.