Question

Find ‘k’ if 2 k- 1, 7, 11are in A.P.

Answer 1

Given:

• 2k -1 , 7 and 11 are in AP .

Find :

• The value of k .

Solution :

• As we know that , In AP common difference is same .

• b - a = c - b

=> 2b = a + c

Here :

• a = 2k-1

• b = 7

• c = 11

=> 2 (7) = 2k-1+11

=> 14 = 2k+10

=> 2k = 14-10

=> 2k = 4

=> k = 4/2

=> k = 2 .

Hence ,the value of k is 2.

I hope it will help you.

Regards.

Answer 2

Answer:

k= 2

Step-by-step explanation:

A1 = 2k-1

A2 = 7

A3 = 11

d = A3-A2 = 11-7 = 4

now d is also equal to A2-A1

so , A2-A1 = 4

7 – (2k-1) = 4

–(2k-1) = 4-7

–(2k-1) = -3

(2k-1) = 3

2k = 3+1

2k = 4

k = 4/2

k = 2