Find the eleventh term from the last term of the AP: 27, 23, 19, ..., –65.

This is a question of CBSE Sample Paper - Class 10 - 2017/18.

You can download the question paper here  https://www.teachoo.com/cbse/sample-papers/

Find the 11th term from last term of AP: 27, 23, 19, ... -65

Question 3 - CBSE Class 10 Sample Paper for 2018 Boards - Part 2
Question 3 - CBSE Class 10 Sample Paper for 2018 Boards - Part 3

Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


Transcript

Question 3 Find the eleventh term from the last term of the AP: 27, 23, 19, ..., 65.AP is 27, 23, 19, , 65 Here a = 27 d = 23 27 = 4 First lets find which term is 65 Let an = 65 a + (n 1) d = 65 Putting values 27 + (n 1) ( 4) = 65 27 + n ( 4) 1( 4) = 65 27 4n + 4 = 65 27 4n + 4 = 65 31 4n = 65 4n = 65 31 4n = 96 n = ( 96)/( 4) n = 24 We need to find out 11th term from the last term Last term = 24th Second last term = 24 1 =23th Third last term = 24 2 = 22nd And so, on So, 11th from last term = (24 10)th term . = 14th term So, we need to find out a14 an = a + (n 1) d Putting values a14 = 27 + (14 1) ( 4) a14 = 27 + (13) ( 4) = 27 52 = 25 So, 11th term from the last = 14th term from the first = 25

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.