Solving a word problem

Question

a gas station sells a total of 4500 gallons of regular gas and premium gas in one day. The ratio of gallons of refular gas sold to gallons of premium gas is 7:2 what is a system of linear equations that represents this situation?

 

how many gallons sold were regular? how many were premium?

 

 

I go the answer just don't know how to show my son doing it the way they do math now...

Answer 1

First, choose variables to represent the unknowns.

 

Let number of regular gallons = R

Let number of premium gallons= P

 

Now you can use these variables to create equations to represent the total number of gallons and the ratio of the two gasses.

 

R + P = 4500         eq1      ------> total number of gallons

R / P = 7 / 2           eq2     ------->  ratio of gasses

 

7P = 2R                 eq2 (rewritten)