Question. Audrey was asleep for 10 hours last night and dreamed for 2/5 of the time. How much of the night was she not dreaming?
Answer. 6
What step-by-step reasoning justifies that answer?
Reasoning: If Audrey was asleep for 10 hours last night and dreamed for 2 / 5 of the time, she dreamed for 2 / 5 * 10 = 4 hours. The total time Audrey slept without dreaming is 10 - 4 = 6 hours.