Answer: 255 Teenagers.
Solution: If 170 is 2/3 of the teenagers then 85 is 1/3. So, 170 + 85 = 255.
:D
Inverse variation is of the form y=k/x or if you prefer yx=k.
z=6.3 bar I assume you mean 6.33333333 forever
10z-z=63.3333...-6.3333
9z=57
z=57/9 (exact)
Now back to the problem...
xz=k, we are told x=3 and we have shown z=57/9 so we can solve for k, the constant of variation
k=3(57/9)=19
So our equation is:
xz=19, now we wish to know what z is when x=8 so
8z=19 divide both sides by 8
z=19/8
z=2.375 (exact, no rounding necessary)
5.40/x=0.75/1
cross multiply:
0.75x=5.40
divide:
0.75x/0.75=5.40/0.75
x=$7.20
just to check:
5.40/3=1.8
1.8*4=7.2
the answer is $7.20 for 1 hour
Area of semicircle is given by:

r is the radius, and we are given the diameter. Radius is half the diameter, so it's 2.5m. Let's plug that into the formula (using 3.14 as an estimation for pi):

So, the area of this semicircle is
9.81m².