这题是进入数学的第一题!! 1. in a 1-mile distance, P finished it in R miles per hours, if the time he used was R+20 per hour, he would have used 4 minute less than the original, what is R? a. 5 b. 10 c. 20 d. E. 忘了。 这题感觉很简单 偏偏我那时候脑袋就当了。。。想了3分钟还是想不起来。。就随便点了答案 C.....
2. If m and r are two postive integers, the sum of the tens digit of m and r is 14, what is the largest possbile value of mr? 求m和r 的 乘积。。