The distance from the midpoint is 6 kilometers, which means that the express train has traveled two more 6 kilometers than the local train (note that it is two), so with 12/0.6=20 (distance difference/time = speed difference), it can be calculated that the express train has traveled 20 kilometers more than the local train in one hour, because the express train has traveled 1.2 times more than the local train.

the second question

We need to find a unified unit. Height: Medium equals 7:4, so the senior grade is 7/4 of the middle grade, and the junior grade is 54 more than 75% of the middle grade. If we take Unit 1 in the middle school as X, the senior class is 7/4x, and the junior class is 75%x+45. Because the height ratio is 270, the equation is 7/4x- (.

I knew it in the middle grade, and I believe you can also calculate the level. A * * * is 1 188 people.