Answer:
The cost of an oil change for 1 truck was $42
Step-by-step explanation:
Let
x -----> the cost of an oil change for 1 truck
y -----> the cost of gas for 1 truck
z ----> the total bill
we know that
[tex]z=11[x+y][/tex]
we have
[tex]z=\$694.32[/tex]
[tex]y=(6)(3.52)=\$21.12[/tex]
substitute and solve for x
[tex]694.32=11[x+21.12][/tex]
[tex]x=(694.32/11)-21.12[/tex]
[tex]x=\$42[/tex]