Question

The 10th term and the 18th term of an A.P. are 25 and 41 respectively then find 38th term of that A.P Similarly if nth term is 99.Find the value of n.
Only right ans plssss....
Surely mark u as a brainliest....​

Answer 1

Answer:

38th term is 81

For Nth term 99 the value of n is 47

Step-by-step explanation:

We have

A10 =25 and A18 = 41

Lets find out the first term

A10 = A1+(n-1)d. Where d is common difference

A1+(10-1)d = 25

A1+9d=25........(1)

A18 = A1 + (n-1)d

41 = A1 +(18-1) d

A1 + 17d = 41.......(2)

Solving (1) and (2)

A1+17d=41

A1+9d=25

—------------

8d=16

d=16/8 = 2

Hence, A1 = 41-17*2 = 41-34 = 7

Now, the 38th term is

A38 = A1 + (n-1)d = 7 + (38-1)*2 = 7 + 37*2 = 7 + 74 = 81

Nth term is 99,find n

An = A1 + (n-1)d

99 = 7 + (n-1)*2

99-7 = 2n-2

92 = 2n-2

2n = 94

n = 47

Answer 2

Answer:

just copy wt I have written in the paper