Chayei Sarah: Sarah Dies

Sarah was 90 years old when Yitzchak was born. Sarah died at the same time as the Akeidas Yitzchak . Sarah was 127 when she died [Bereishis 17:17, 23:1].

Question: How old was Yitzchak at the time of the Akeida? 

Answer: 127 years – 90 years = 37 years