题目

Rose didn’t see her school IC card at lunch time. She asked her classmates and looked for it everywhere. But she couldn’t   31   it. Later, one girl said that she saw Kate take a card from Rose’s desk. So Rose got very   32   . When she met Kate in the afternoon, Rose   33  , “You have stolen(偷) my card!” Hearing this, Kate began to cry, “No, no, I didn’t steal it! I only took it by   34   .” But Rose didn’t think so and they began to fight. Just then a teacher came up and   35   what had happened. Kate told the whole story. She said her pen pal c已知A，B两地相距50千米，某日下午甲、乙两人分别骑自行车和骑摩托车从A地出发驶往B地如图所示，图中的折线PQR和线段MN分别表示甲、乙两人所行驶的路程S（千米）与该日下午时间t（时）之间的关系．请根据图象解答下列问题：（1）直接写出：甲骑自行车出发　 　小时后，乙骑摩托车才开始出发；乙骑摩托车比甲骑自行车提前　 　小时先到达B地；（2）求出乙骑摩托车的行驶速度；甲骑自行车在下午2时至5时的行驶速度；（3）当甲、乙两人途中相遇时，直接写出相遇地与A地的距离．