Well u do 31.2 x 18 which is 561.6 then u divide by 2 because the formula for a triangle is base x height divided by 2 so It is 280.8
Answer:
C(t)= 15 + 30t
D(t)= 40 + 20t
Step-by-step explanation:
Fixed cost means that a customer will pay that no matter what, the per hour charge is the only thing that will change.
I suppose you want to solve the following equation for b:

First of all, you need to divide both sides by 9:

Then, subtract 2 from both sides:

20% of $50 is:
$50* (20/100)= $10.
$50- $10= $40
The new price is $40.
Hope this helps~