Answer:
D. 1200 gallons
Step-by-step explanation:
Fractions of the total are given, as is the quantity the difference of those fractions represents. These can be used to write an equation to find the total.
<h3>Setup</h3>
Let g represent the total number of gallons of fuel sold. Then the number of gallons of 87-octane sold is 0.50g, and the number of gallons of 89-octane sold is 0.35g. The difference is said to be 180 gallons:
0.50g -0.35g = 180
<h3>Solution</h3>
Collecting terms gives ...
0.15g = 180
Dividing by the coefficient of g, we find ...
g = 180/0.15 = 1200
The gas station sold 1200 gallons of fuel last weekend.
__
<em>Additional comment</em>
That's 600 gallons of 87-octane; 420 gallons of 89-octane; 120 gallons of 92-octane; and 60 gallons of 99-octane.
