You fill your car with 15 gallons of gas at a cost of $45. Using fractional notation, how do you write a proportion that shows how much 5 gallons of gas will cost? Use x to represent the unknown cost.
The proportion can be written as:
15 gallons / $45 = 5 gallons / x
In fractional notation, this would be:
15/45 = 5/x
To write a proportion that shows how much 5 gallons of gas will cost using fractional notation, we can set up the following equation:
(15 gallons)/(cost of 15 gallons) = (5 gallons)/(x)
To find the cost of 5 gallons, we can cross multiply:
(15 gallons)(x) = (5 gallons)(cost of 15 gallons)
15x = 5(cost of 15 gallons)
Cross multiplying gives us:
15x = 75
To solve for x, we divide both sides by 15:
x = 75/15
Simplifying the fraction gives us:
x = 5
Therefore, 5 gallons of gas will cost $5.
To write the proportion, we need to establish the relationship between the gallons of gas and their cost. In this case, we are given that 15 gallons of gas cost $45. We can write this as a fraction:
15 gallons / $45
Now, to find the cost of 5 gallons of gas, we can set up a proportion using the given information. Let's use "x" to represent the unknown cost:
15 gallons / $45 = 5 gallons / x
We can start by cross-multiplying:
15 * x = 5 * $45
Next, we can simplify:
15x = 225
Finally, divide both sides of the equation by 15 to solve for x:
x = 225 / 15
Simplifying further, we get:
x = 15
Therefore, 5 gallons of gas will cost $15.