Question

Margot spent $400 this month on propane to heat her home. Her propane company charges $3 per gallon and she received a $20 discount for paying in cash.

To determine how many gallons of propane she bought, solve for x in the following equation:
400 = 3x - 20

Answer 1

To find how many gallons of propane Margot bought, the algebraic equation 400 = 3x - 20 is solved by first adding 20 to each side and then dividing by 3, resulting in 140 gallons of propane.

Step-by-step explanation:

The student is tasked with solving the equation 400 = 3x - 20 to determine the amount of propane in gallons that Margot purchased. This is a basic algebra problem where x represents the number of gallons of propane.

To solve for x, we first need to isolate the variable on one side of the equation. We can start by adding 20 to both sides of the equation to cancel out the minus 20 on the right:

400 + 20 = 3x - 20 + 20
420 = 3x

Next, we divide both sides by 3 to solve for x:

420 / 3 = 3x / 3
x = 140

Therefore, Margot bought 140 gallons of propane.