Question #95164

1 Answer
Sep 22, 2017

See below

Explanation:

a) Equations expressing how the fuel costs vary with the miles travelled:

Diesel:

#C_d=15m# where #C_d# is the cost of diesel and #m# is the # of miles.

Petrol:

#C_p=20m# where #C_p# is the cost of petrol and #m# is the # of miles.

b) Since the cost is in cents and assuming there are 100 cents to the euro, the equation would be:

#0.15m>=12000#

#m>= 80000# miles

There might be more to this one?

c) If the prices of both types of fuel fall by 25% that means:

Diesel:

#15(0.25)=3.75#

so the new price is:

#15-3.75=11.25# cents

OR

you can do the calculation in one shot by multiplying by #1-0.25# since it a percent decrease:

#15(1-0.25)=15(0.75)=11.25# cents

Petrol:

#20(0.75)=15# cents.

I hope this is of some help.