Question

The first term of an A.P. is unity and the common difference is 4, which of the following will be a term of this A.P. (a ) 4551 (b ) 10091 ( c ) 7881 ( d ) 13531​

Answer 1

Starting with n = 0, the n-th term in the sequence is

4n + 1

so any number in the sequence must have a remainder of 1 when divided by 4.

We have

4551 = 1137×4 + 3

10091 = 2522×4 + 3

7881 = 1970×4 + 1

13351 = 3382×4 + 3

Answer 2

c

Explanation:

first term=1

common d=4

nth term=a+(n-1)d

7881=1+(n-1)4

7881=1+4n-4

7884=4n

n=1971