When ~$\frac{2}{3}$~of the garments in a shipment were inspected, 18 of the garments passed inspection and the remaining 2 garments failed. How many of the uninspected garments must pass inspection in order that 90 percent of the garments in the shipment pass?
10
9
8
7
5
2/3x=18+2,所以x=30,30*0.9=27,27-18=9
题目翻译:当 2/3的货物被检查的时候,有 18 个过了,2个没过。问剩下的还需要过多少个才能保证 90%的通过率。 思路点拔:先算总量,再算剩下量,再算需要通过多少。
题目全解:已过的 18+2=20,总量 30,还剩 10 个,10*90%=9。选 B。