Kabir's mother keeps a record of his birthday on When he was One year old, his height was 70 cm, at 2 years he was 80 cm tall and 3 years he was 90 cm tall. His mother was studying in the 10th class. She said, it seems like Kabir's height grows in Arithmetic Progression. Assuming this, she calculated how tall Kabir will be the age of 15 years when she is in the 10th! Kabir grows in A.P, and finds his height at the age of 15 years.