某测量员站在两平行峭壁间某一位置鸣枪,经过1.005s第一次听到回声,又经过0.505s再次听到回声,则两峭壁间的距离为多少?(已知当时声速为340m/s)
The boy is too young and he needs his mother____ (dress) him.
解方程或解比例。
①6x-18=36
②x- 34 x=2
③ 1.20.5 = 3x