What is the midpoint of -4 and 20?

In one dimensions (i.e. with standard numbers and not points with more coordinates) the midpoint is the same as the average.

The average of two numbers is their sum divided by two.

So, we have -4+20=16. Divide this by two to get 8.

8

Step-by-step explanation: 4+20=24

24/2= 12

-4+12 = 8

Total time taken in entire trip = 220 minutes

Step-by-step explanation:

For Downwind  : Bird speed = 18 miles/hour

                            time taken = x hours

                       total distance = speed x time taken

                                               =  18 (x) = 18x

for returning  speed   3 miles per hour slower that is 18-3 = 15 miles per hour

time taken = x hours

and distance traveled =  5 miles lesser than previous that is 18x -5

that is from above

15x =  18x -5

15x-18x = -5

-3x = -5

3x =5

x = hours or 100 mins.

total distance taken for   returning  =   18 () = 30  miles

time taken for return = hours or 120 minutes

therefore total time taken for the entire journey = 100 +120 = 220 minutes.