1.一楼的已经做了
2.设乙的速度为x m/s.
3*60=180(秒）
200*6-（40*6+40x）=200x
x=4
(40*6+40*4)/3就能得出直径
3.设这批苹果为单位1,甲等苹果每千克应卖多少X元.
0.7（7÷12）+X（5÷12）-0.8=0.8×25%
4.设两城相距x千米.
（x-200)/(x/10)=200/(x/15)
自己解吧,我时间不够
1.Is the frog is catching mosquitoes with its tongue?
2.How many sleeping days does your father have?
3.them food eat