Advertisement Remove all ads

If the 3rd and the 9th Terms of an Arithmetic Progression Are 4 and -8 Respectively, Which Term of It is Zero? - Mathematics

Sum

If the 3rd and the 9th terms of an arithmetic progression are 4 and -8 respectively, Which term of it is zero?

Advertisement Remove all ads

Solution

For an A.P

`t_3 = 4`

=> a +2d = 4 .....(i)

`t_9 = -8`

=> a + 8d = -8 ....(ii)

Substractinjg (i) from (ii) we get

6d = -12

=> d = -2

Substituting d = -2 in (i) we get

a + 2(-2) = 4

=> a - 4 = 4

=> a = 8

=> general term = `t_n = 8 + (n - 1)(-2)`

Let pth term of this A.P be 0

`=> 8 + (p - 1) xx (-2) = 0`

`=> 8 - 2p + 2 = 0`

=> 10 - 2p = 0

=> 2p = 10

=> p = 5

Thus 5th term of this A.P is 0.

Concept: Arithmetic Progression - Finding Their General Term
  Is there an error in this question or solution?
Advertisement Remove all ads

APPEARS IN

Selina Concise Maths Class 10 ICSE
Chapter 10 Arithmetic Progression
Exercise 10 (B) | Q 5 | Page 140
Advertisement Remove all ads
Advertisement Remove all ads
Share
Notifications

View all notifications


      Forgot password?
View in app×