Question

8. एका अंकगणिती श्रेढीचे दुसरे पद 13 आणि पाचवे पद 25 असेल तर तिचे 7 वे
पद?
(A) 30
(B) 33
(C) 37
(D) 38​

Answer 1

SOLUTION

TO CHOOSE THE CORRECT OPTION

If the second term of an arithmetic series is 13 and the fifth term is 25, then its 7th

(A) 30

(B) 33

(C) 37

(D) 38

EVALUATION

Let first term = a

Common Difference = d

Then

2nd term = a + d

5th term = a + ( 5 - 1 )d = a + 4d

7 th term = a + ( 7 - 1 )d = a + 6d

So by the given condition

$\sf{a + d = 13} \: \: \: - - - - (1)$

$\sf{a +4 d = 25} \: \: \: - - - - (2)$

Now Equation 2 - Equation 1 gives

3d = 12

$\sf{ \implies \: d = 4}$

From Equation 1 we get

a = 13 - 4 = 9

∴ 7 th term

= a + 6d

= 9 + 24

= 33

FINAL ANSWER

Hence the correct option is (B) 33

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