Question 8 (OR 2 nd question)
If 7 times the 7 th term of an A.P is equal to 11 times its 11 th term, then find its 18th term.

Subscribe to our Youtube Channel - https://you.tube/teachoo
Last updated at Oct. 1, 2019 by Teachoo
Question 8 (OR 2 nd question)
If 7 times the 7 th term of an A.P is equal to 11 times its 11 th term, then find its 18th term.
Subscribe to our Youtube Channel - https://you.tube/teachoo
Transcript
Question 8 (OR 2nd question) If 7 times the 7th term of an A.P is equal to 11 times its 11th term, then find its 18th term. We know that an = a + (n – 1)d Given that 7 times the 7th term is equal to 11 times its 11th term 7 × a7 = 11 × a11 7 × (a + (7 – 1)d) = 11 × (a + (11 – 1)d) 7 × (a + 6d) = 11 × (a + 10d) 7a + 42d = 11a + 110d 7a – 11a = 110d – 42d –4a = 68d a = 68𝑑/(−4) a = –17d Now, we need to find the 18th term a18 = a + (18 – 1)d = a + 17d Putting a = –17d = –17d + 17d = 0 So, 18th term is 0
CBSE Class 10 Sample Paper for 2019 Boards
Question 1
Question 2 (Or 1st)
Question 2 (Or 2nd)
Question 3 (Or 1st)
Question 3 (Or 2nd)
Question 4
Question 5
Question 6
Question 7 (Or 1st)
Question 7 (Or 2nd)
Question 8 (Or 1st)
Question 8 (Or 2nd) You are here
Question 9
Question 10
Question 11
Question 12
Question 13
Question 14
Question 15
Question 16 (Or 1st)
Question 16 (Or 2nd)
Question 17 (Or 1st)
Question 17 (Or 2nd)
Question 18
Question 19 (Or 1st)
Question 19 (Or 2nd)
Question 20
Question 21 (Or 1st)
Question 21 (Or 2nd)
Question 22
Question 23 (Or 1st)
Question 23 (Or 2nd)
Question 24
Question 25
Question 26
Question 27 (Or 1st)
Question 27 (Or 2nd)
Question 28 (Or 1st)
Question 28 (Or 2nd)
Question 29
Question 30
About the Author