A car company charges a flat rate for hiring a car and also charges at per mile rate for usage. Its charge for $18$ $18$ miles is $$ 18.79$ $$18.79$ and for $25$ $25$ miles is $$ 22.29$ $$22.29$ . What is the charge per mile and flat rate?

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Answer 1 · 2016-10-25T02:24:20

Charges per mile are $$ 0.50$ $$0.50$ and flat rate is $$ 9.79$ $$9.79$ .

Let $x$ $x$ =charge per mile
$y$ $y$ = flat rate

$18 x + y = 18.79$ $18x + y = 18.79$
$25 x + y = 22.29$ $25x + y= 22.29$

From first equation, we get $y = 18.79 - 18 x$ $y=18.79-18x$ . Using substitution...

$25 x + (- 18 x + 18.79) = 22.29$ $25x + (-18x + 18.79) = 22.29$

or $7 x = 22.29 - 18.79 = 3.50$ $7x=22.29-18.79=3.50$

i.e. $x = \frac{3.50}{7} = 0.50$ $x=3.50/7=0.50$

Substitute $0.50$ $0.50$ for $x$ $x$ in any equation

$18 (0.50) + y = 18.79$ $18(0.50) + y =18.79$

or $9.00 + y = 18.79$ $9.00+y=18.79$

i.e. $y = 18.79 - 9.00 = 9.79$ $y=18.79-9.00=9.79$

A car company charges a flat rate for hiring a car and also charges at per mile rate for usage. Its charge for 1818 miles is $18.79$18.79 and for 2525 miles is $22.29$22.29. What is the charge per mile and flat rate?