A car company charges a flat rate for hiring a car and also charges at per mile rate for usage. Its charge for #18# miles is #$18.79# and for #25# miles is #$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# and flat rate is #$9.79#.

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

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

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

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

or #7x=22.29-18.79=3.50#

i.e. #x=3.50/7=0.50#

Substitute #0.50# for #x# in any equation

#18(0.50) + y =18.79#

or #9.00+y=18.79#

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