To find the total amount needed for the trip, we can set up the equation based on the information given. We know that the $55 earned is one-third of the total amount needed.
Let's denote the total amount needed as \( x \).
According to the problem: \[ \frac{1}{3}x = 55 \]
To solve for \( x \), we can multiply both sides of the equation by 3: \[ x = 55 \times 3 \] \[ x = 165 \]
Therefore, the total amount needed for the trip is $165.