Question

Micah is keeping track of how much he spends this month on gas. In the first week, he bought x gallons of gas at $2.39 per gallon. In the second week, he bought 3 fewer gallons of gas than the first week at $2.49 per gallon. So far this month, he has spent a total $46.21 on gas. How many gallons did he purchase in the first week and second week (not combined)

Answer 1

Micah bought 11 gallons in the first week and 8 gallons in the second week.

Explanation:

In the first week, he bought x gallons of gas at $2.39 per gallon, making a total amount of
`2.39x`.

In the second week, he bought 3 fewer gallons of gas than the first week at $2.49 per gallon.

Amount becomes
`(x-3)2.49`

And he has spent a total $46.21 on gas.

Equation becomes:

`2.39x+(x-3)2.49=46.21`

Solving for x now;

`2.39x+2.49x-7.47=46.21`

=>
`4.88x=46.21+7.47`

=>
`4.88x=53.68`

x = 11

And for second week he bought
`11-3=8` gallons

Micah bought 11 gallons in the first week and 8 gallons in the second week.

Answer 2

Micah bought 11 gallons of gas in the first week and 8 gallons of gas in the second week

Explanation:

Let x be the number of gallons Micah bought the first week. In the second week, he bought 3 fewer gallons of gas than the first week, so he bought x-3 gallons in the second week.

In the first week, he bought x gallons of gas at $2.39 per gallon and paid $2.39x. In the second week, he bought x-3 gallons of gas at $2.49 per gallon and paid $2.49(x-3). This month, he has spent a total $46.21 on gas.

Hence,

`2.39x+2.49(x-3)=46.21\\ \\239x+249(x-3)=4,621\ [\text{Multiplied by 100}]\\ \\239x+249x-747=4,621\\ \\488x=4,621+747\\ \\488x=5,368\\ \\x=11\\ \\x-3=11-3=8`