Answer:
A) x = 225 - 7.5p
B) x = 180 millions of gallons
Step-by-step explanation:
A) Make "x" the subject:
[tex]\sf \rightarrow 0.4x + 3p = 90[/tex]
[tex]\sf \rightarrow 0.4x = 90-3p[/tex]
[tex]\sf \rightarrow x = \dfrac{90-3p}{ 0.4}[/tex]
[tex]\sf \rightarrow x = 225-7.5p[/tex]
B) Demand when the price per gallon is $6:
substitute p = 6
[tex]\sf \rightarrow x = 225-7.5(6)[/tex]
[tex]\sf \rightarrow x = 225-45[/tex]
[tex]\sf \rightarrow x =180[/tex]
