題目:Both T and W offer money back guarantees on their fold-up treadmills. Because customers only take advantage of these guarantee when the treadmills malfunction, and T receives more requests for money back, it must be true that T treadmills malfunction more often than do W treadmills. 答的假設是: everyone with a broken treadmill asks for a refund. 我自己想的是: 兩家公司賣的數量相當 因此不會是因為T賣的多 壞的也多 但是毀損率其實相當... 我想請教的是 我這樣的想法有可能是答案嗎 接近ETS的思考邏輯嗎 還是哪有瑕疵? 先多謝指點了!