Liza earned some money delivering newspapers. She bought a battery for $1.95, and gave her mother $30. She bought a ring for $7.20, and then spent half of the remaining money on a radio. If Liza has $38.50 left, How much money did she earn delivering newspapers?

The answer is $116.15

Hi,

here's the answer to your question:

Let x = the initial amount Liza earned from delivering newspapers. Work your way backward. She has $38.50 that is left over. Since she spent the same amount on a radio, the radio costs $38.50. She spends $7.20 (ring) + $1.95 (battery) before this and gives her mom $30. All of these are subtractions from the initial amount: x - 1.95 - 30.00 - 7.20 - 38.50 = 38.50 x - 77.65 = 38.50 x = $116.15