Answer
a)
i) C=0.04$x$
ii) C= 0.12$x$
b)
i) $400
ii) $1200
Work Step by Step
a)
i) Let the energy cost be C in dollars.
To find the energy cost, it's the cost of one mile multiplied by how many miles you're traveling divided by 100cents to find the cost in dollars.
C=$\frac{4x}{100}$
C= $0.04x$
ii) Let the energy cost be C in dollars.
C=$\frac{12x}{100}$
C=$0.12x$
b)
i) $0.04\times10000$=$400$
ii) $0.12\times10000=$$1200
