Mary and Rose went shopping to buy presents. They spent the same amount. Mary bought two pairs of sunglasses for $50 each and a pair of jeans for $100. Rose bought a pair of shoes at $150 and two decks of basketball cards. How much did one deck of basketball cards cost? Think carefully first, then make a decision:

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
Two pairs of sunglasses costs 2 x $50 = $100. So, Mary spent $100 + $100 = $200. Thus, two decks of basketball cards costs $200 - $150 = $50. Therefore, one deck of basketball cards costs $50 / 2 = $25. So, the answer is 25.