Kabir’s mother keeps a record of his height on each birthday. When h

1.	Kabir’s mother keeps a record of his height on each birthday. 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 aunt Meera 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 at the age of 15 years when he is in 10th! She was shocked to find it. You too assume that Kabir grows in A.P. and find out his height at the age of 15 years.
Answer» Height of Kabir when he was 1 year old = 70 cm Height of Kabir when he was 2 years old = 80 cm Height of Kabir when he was 3 years old = 90 cm The heights of Kabir form an A.P. Here, a = 70, d = 80 – 70 = 10 We have to find height of Kabir at the age of 15years i.e. t₁₅ . Now, t_n = a + (n – 1)d ∴ t₁₅ = 70 + (15 – 1)10 = 70 + 14 × 10 = 70 + 140 ∴ t₁₅ = 210 ∴ The height of Kabir at the age of 15 years will be 210 cm.

Kabir’s mother keeps a record of his height on each birthday. 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 aunt Meera 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 at the age of 15 years when he is in 10th! She was shocked to find it. You too assume that Kabir grows in A.P. and find out his height at the age of 15 years.

Answer»

Height of Kabir when he was 1 year old = 70 cm Height of Kabir when he was 2 years old = 80 cm

Height of Kabir when he was 3 years old = 90 cm The heights of Kabir form an A.P.

Here, a = 70, d = 80 – 70 = 10

We have to find height of Kabir at the age of 15years i.e. t₁₅ .

Now, t_n = a + (n – 1)d

∴ t₁₅ = 70 + (15 – 1)10

= 70 + 14 × 10 = 70 + 140

∴ t₁₅ = 210

∴ The height of Kabir at the age of 15 years will be 210 cm.