Mathematics · Chapter 5 · NCERT Examples
Verified NCERT questions and solutionsSolutions are checked independently and follow the supplied NCERT chapter edition.
Find the 11th term from the end of 10,7,4,…,−62.
Solution
Board-exam working:
Here a=10,d=−3,l=−62.
First find the number of terms: −62=10+(n−1)(−3)=13−3n.
Thus 3n=75 and n=25.
The 11th term from the end is term number 25−11+1=15 from the start.
a₁₅=10+(15−1)(−3)=10−42=−32.
Check from the end: −62+(11−1)3=−62+30=−32.