Luo Hao held a card with 49 in one hand and a card with 94 in the other, and asked Zhang Liang to guess which card was in which hand. Zhang Liang asked Luo Hao to answer the following question: "Please multiply the number in the left hand by 2, divide the number in the right hand by 2, and then add the two numbers. Is the sum odd or even?" When the sum was said to be an odd number, Zhang Liang immediately guessed that the card with 49 was in Luo Hao's left hand. Do you know why?
罗浩一手握着写有49的卡片，另一手握着写有94的卡片，请张亮猜哪张在哪只手中．张亮请罗浩回答了下面一个问题："请将左手中的数乘2，右手中的数除以2，再将这两个数相加，这个和是奇数，还是偶数？"当罗浩说出和是奇数时，张亮马上就猜到写有49的卡片在罗浩的左手中．你知道为什么吗？
<result>49</result>