GWD 7-37

小腾

Q37:

During a trip, Francine traveled x percent of the total distance at an average speed of 40 miles per hour and the rest of the distance at an average speed of 60 miles per hour. In terms of x, what was Francine’s average speed for the entire trip?

为何我算出来答案是120/(X+2)，选项里没有，哪错了呀？不明白，请高手指点。

leadership

100 100 x 120 12000

--------- = --------- = ---------- so, E

X/40 + (100-X)/60 3X + 200 - 2X X + 200

小腾

明白了，我是设的X就是百分数，不是PERCENT，这是为这错的第二题了.