Answer:
This is an experiment because a treatment was applied to a group.
Step-by-step explanation:
This is because it cannot be a survey since the children are taking a test, which has a hypothesis. Hope you get this right. I took the test and got right.
The answer to your question above would be: 7z-2/z-7
Step-by-step explanation:
red one has 108
then green one has 108/2
then m=54