Questions: Ebbinghaus found that about one day after you learn new material, you will only remember percent of it if you have not reviewed it a second time 90 50 70 30

The answer is the second one (50): about one day after you learn new material, you will only remember 50 percent of it if you have not reviewed it a second time.

Explanation for each option:

• 90: This is incorrect. Ebbinghaus's forgetting curve suggests a significant drop in retention after one day without review, so remembering 90% is too high.

• 50: This is correct. Ebbinghaus's research on memory and forgetting indicates that without review, retention drops to about 50% after one day.

• 70: This is incorrect. While 70% retention might occur shortly after learning, it is not consistent with the typical drop seen after one day without review.

• 30: This is incorrect. Although memory retention continues to decline over time, 30% is lower than what Ebbinghaus found for one day after learning without review.

In summary, Ebbinghaus's studies on memory retention show that without reviewing, you will remember about 50% of new material one day after learning it.