Answer:
$654
Step-by-step explanation:
Let the amount of money Marlina's received for her salary be x.
We know that she spent 1/2 of her salary on rent and then $338 on her electric and water bill. So, after this, she will have:

Left of her salary.
Next, she spent one half of what was left. So, it will be one-half of the equation. Therefore, she will have spent:

Finally, she spent $56 for gas. So, we will subtract 56:

And we know that after all of the expenses, she will have $102 left. Therefore:

We want to know how much Marlina spent on rent. So, let's find her salary x first.
First, let's distribute the 1/2:

Combine like terms:

Evaluate:

Add 225 to both sides:

Multiply both sides by 4:

Therefore, Marlina received a total of $1308 for her salary.
We know that she spent half of her salary on rent. Therefore, the amount she spent on rent is:

And we're done!