Question

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

Answer 1

Solution:

Given A.P:27,23,19, ..., –65.

i ) first term (a) = 27

common difference (d)=a2-a1

= 23-27

= -4

Now ,

arranging the sequence in reverse order, we get

-65, -61,....,23,27

first term (a) = -65

d = a2-a1 = -61 -(-65)

= -61+65

= 4

n = 11

nth term (an) = a+(n-1)d

= -65+(11-1)4

= -65+10×4

= -65+40

= -25

Therefore,

-25 is the eleventh term from the last term of the AP: 27,23,19, ..., –65.

••••

Answer 2

Let the AP be -

-65....,19,23,27

a = -65

d= 4

n= 11

ath term = a+ (n - 1) d

11 th term = -65 + 10* 4

-65+ 40

= -25

Therefore 11 th term from the last is equal to -25

Hope it helps you