How old was Abraham when he died?

Answer: 175 years

Abraham lived a total of 175 years and was buried by Isaac and Ishmael in the cave of Machpelah.

“Abraham lived a total of 175 years. And at a ripe old age he breathed his last and died, old and contented, and was gathered to his people. His sons Isaac and Ishmael buried him in the cave of Machpelah near Mamre, in the field of Ephron son of Zohar the Hittite.”— Genesis 25:7-9 (BSB)