According to Exodus 12:40, how long did the Israelites live in Egypt?

Answer: 430 years

The Israelites' stay in Egypt lasted 430 years; at the end of the 430 years, to the very day, they went out of Egypt.

“Now the duration of the Israelites’ stay in Egypt was 430 years. At the end of the 430 years, to the very day, all the LORD’s divisions went out of the land of Egypt.”— Exodus 12:40-41 (BSB)