an important question from the book -ML aggarwal( avichal publication)class 10th , chapter9, arithmetic progression …….. This type of question has been asked in paper. so please solve it in detail. we have been asked
Find the 20th term from the last term of the AP 3, 8, 13, 253?
Class 10, ML Publication, Arithmetic Progression Chapter 9 question no. 8(i)
Rajan@2021Guru
Find the 20th term from the last term of the AP 3, 8, 13, 253?
Share
For the given A.P.,
First term(a)=3
Last term(tn)=253
Common Difference(d)=8−3=5
∵tn=a+(n−1)d
⇒253=3+(n−1)×5
⇒253−3=(n−1)×5
⇒250÷5=n−1
⇒50+1=n
∴n=51
In 51 terms, 20th term from the last term will be 51−20+1=32th
∴t32=a+(32−1)d=3+31×5=3+155=158