Answer:
78°F
Explanation:
If the temperature was 75.5°F, and it rose by 6°F on Sunday, then the temperature on Sunday was:
75.5°F + 6°F = 81.5°F
If the temperature on Sunday was 81.5°F, and it dropped by 3.5°F on Monday, then the temperature on Monday was:
81.5°F - 3.5°F = 78°F
Therefore, the temperature on Monday was 78°F.