Adv
Rajan@2021
  • 1
Guru

An AP 5, 12, 19,……has 50 terms. Find its last term. Hence, find the sum of its last 15 terms.

  • 1

An important and exam oriented question from arithmetic progression chapter as it was already asked in previous year paper of 2015 in which we are to calculate the last term and its sum of last 15 terms, if An AP 5, 12, 19,……has 50 terms.

Book RS Aggarwal, Class 10, chapter 5C, question no 34(i)

Share

1 Answer

  1. a=5,d=125=7,n=50

    Last term,

    an=a+(n1)d

    =5+(501)7=348

    Sn=n/2[2a+(n1)d]

    =50/2[2(5)+(501)7]

    =25[10+49×7]

    =8825

    • -2
Leave an answer

Leave an answer

Browse

Choose from here the video type.

Put Video ID here: https://www.youtube.com/watch?v=sdUUx5FdySs Ex: "sdUUx5FdySs".

Captcha Click on image to update the captcha.

Related Questions