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
Let's use x to represent the unknown cost of 5 gallons of gas.
We know that 15 gallons of gas cost $45. So we can write the proportion:
15 gallons / $45 = 5 gallons / x
To find x, we need to cross multiply:
15x = 5 * $45
15x = $225
Now, divide both sides by 15 to solve for x:
x = $225 / 15
x = $15
Therefore, 5 gallons of gas will cost $15.
Determine if 2.510=?1248 or 2.52=?1224 is a proportion
To determine if 2.510 ? 1248 or 2.52 ? 1224 is a proportion, we need to cross multiply.
For 2.510 ? 1248:
Cross multiplying gives us 2.510 * 1224 = 2.52 * 1248.
This simplifies to 3062.24 = 3129.6, which is not true.
So, 2.510 ? 1248 is not a proportion.
For 2.52 ? 1224:
Cross multiplying gives us 2.52 * 1224 = 2.52 * 1224.
This simplifies to 3080.48 = 3080.48, which is true.
So, 2.52 ? 1224 is a proportion.
To write a proportion that shows how much 5 gallons of gas will cost, we can set up a ratio using the given information.
Cost of 15 gallons / 15 gallons = Cost of 5 gallons / 5 gallons
Using fractional notation, we can write this as:
$45 / 15 gallons = x / 5 gallons
Simplifying this proportion, we have:
(45/15) = (x/5)
Dividing both sides by 3 to simplify, we get:
(45/15) * (1/3) = (x/5) * (1/3)
3 = x/5
Finally, we can multiply both sides by 5 to find the value of x:
x = 3 * 5
Therefore, 5 gallons of gas will cost $15.