Question

Which term of the A.P.:1, 4, 7, ... is 25?​

Answer 1

Answer:

the ninth term of the will be 25

Step-by-step explanation:

using the formula of general term of an ap

an=a+(n-1)d

the value of an =25

a=1

d=3

now obtain values of n

answer :- n=9

Answer 2

Given,

The AP series is = 1,4,7..... so on.

To find,

The number of term in the given AP which has a value of 25.

Solution,

Let, the the term is nth term.

(Assume, n as a variable to do the further mathematical calculations.)

Now, we have to calculate the value of the nth term with the following mathematical formula.

nth term = a+(n-1)d

Here,

a = first term of AP

n = number position of the term

d = common difference

Now,

a = 1

n = ?

d = second term - first term = 4-1 = 3

By putting the values we get that,

25 = 1+(n-1)×3

25 = 1+3n-3

3n-2 = 25

3n = 27

n = 9

Hence, 25 is the 9th term of the given AP.