Let S = his average speed.
Let D = distance traveled one way
Time = distance / speed
Set up an equation:
d/6 + d/12 = 2d/S
Multiply the equation by 12s:
12s(d/6) + 12s(d/12) = 12s(2d/s)
Simplify to get:
2sd + sd = 24d
Combine like terms:
3sd = 24d
Divide both sides by d:
3s = 24
Divide both sides by 3:
s = 24/3
s = 8
His average speed was 8 mph.
Answer:

Step-by-step explanation:
we have

For 
substitute the value of x and the value of y in the expression





Answer:
8,6,3, v= 144
4,8,6, v=192
15,10,6, v=900
Step-by-step explanation:
I’m x is degrees since is downs