On a recent trip, Cindy drove her car 290 miles, rounded to the nearest 10 miles, and used 12 gallons of gasoline, rounded to the nearest gallon. The actual number of miles per gallon that Cindy's car got on this trip must have been between. 答案是:285/12.5 and 295/11.5 为什么不是285/12.4 and 294/11.5 根据rounding的规则,290这个数字原来的范围应该是285-294啊,为什么OG的解释里是285-295呢,12这个数字也是这样。难道rounding并不是四舍五入? |