The answer is 80 ft.
Based on the diagram we know that the tree triangle and the building triangle are similar triangles where the lengths of each are proportional to the other.
The lengths of the triangle the tree makes are half of the lengths of the building triangle. So this problem can be solved using ratio and proportion:

to solve for x, all you need to do is cross multiply then divide.
The answer is then 80ft.
Another way to solve this is just by using logic. If the lengths of the tree triangle is half of the building, simply divide the lengths of the building triangle by two.
160ft/2 = 80ft.
1/3 if you have a positive and a negative, it will turn into a positive so 11/12-7/12
I believe the answer is -1/5 hope this helps
I don't see a diagram, but if the portion of the tennis region you are asked to analyze doesn't intersect anywhere else/any other regions pertaining to other sports, wouldn't the sport chosen by these students be solely tennis?
-6b > 42 = b<-7
or
4b > -4 = b>-1
Hope this helps.