Answer:
28
Step-by-step explanation:
40% 6th graders of 70 total = 28 6th graders
40% 6th graders + 20% 7th graders = 60%
100% - 60% = 40% 8th graders
40% are 8th graders therefore the answer is 28
270 solve that yourself lol
Answer:

Step-by-step explanation:
the unit of length is meter,
so, 80cm=0.8cm, 10cm=0.1m
the length of the rail=
=
The hypothesis is sometimes the if part in my opinion
960,000! Hope this helped! :D