Final answer:
To find the new temperature after an increase of Y degrees from an initial temperature of 55 degrees, you add the increase to the initial temperature, resulting in 55 + Y degrees as the new temperature.
Step-by-step explanation:
If the temperature in Seattle is 55 degrees and it increases by (Y) degrees, the new temperature is given by the initial temperature plus the increase in temperature. Therefore, the correct answer is: b) 55 + Y degrees.
When calculating temperature changes, it's important to add the increase to the initial temperature. Similarly, if the temperature were to decrease by Y degrees, you would subtract Y from the initial temperature. Here's how it works in a formula: New Temperature = Initial Temperature + Temperature Increase. Applying this to the given problem, if the temperature is initially 55 degrees and increases by Y degrees, the new temperature would be 55 + Y degrees.