Question: $50 upfront charge and 0.20cents per km

A) cost equation for kilometres traveled(d)

B) $120 is the cost, what is the distance traveled

Let \(\displaystyle C\) = Total cost

Let \(\displaystyle d\) = Distance traveled

They charge to $50.00 plus $0.20 every km.

So,

\(\displaystyle C=0.20d+50\)

If the total cost is $120.00

Then

Let \(\displaystyle C=120\)

Substitute.

\(\displaystyle 120=0.20d+50\)

Solve for \(\displaystyle d\)

Subtract both sides with 50

\(\displaystyle 120-50=0.20d+50-50\)

\(\displaystyle \Rightarrow\)

\(\displaystyle 70=0.20d\)

Multiply both sides by 5 (to make 0.20=1)

\(\displaystyle 70*5=0.20d*5\)

\(\displaystyle \Rightarrow\)

\(\displaystyle 350=d\)