Two thirds of an hour =40 minutes =2400 seconds.
4/9 hours = 1600 seconds
600000÷2400=250
M/s < 3× 10? Every second = 300m/s.
600000÷ 1600=375
M/s > 3× 10? Every second = 300m/s.
So the second plane is supersonic.
2、2^a=3
2^b=6
2^c= 12
2^b=6=3×2=2^a×2=2^(a
1)
∴b=a
1
b-a= 1>0
B > a。
2^c= 12=6×2=2^b×2=2^(b
1)
∴c=b
1
c-b= 1>0
That's c > b
∴c>b>a
Similarly:
a