Answer:
1 hour
Explanation:
Firstly, retroactive interference is the effect of new memories holding back a person from keeping older memories. According to my research many scientists believe that if you study or read certain information 1 hour before going to sleep it greatly reduces the likely-hood of suffering from retroactive interference. Therefore it will help you remember what you read for the test the next day.
I hope this answered your question. If you have any more questions feel free to ask away at Brainly.