1.

The sum of the first term and the last term of an AP is 51. The second last term is 42. Find the second term.1. 92. 73. 84. 6

Answer» Correct Answer - Option 1 : 9

Given: The sum of the first term and the last term is 51. The second last term is 42.

Formula:

Nth term of an AP, Tn = a + (n - 1)d, where ‘a’ is the first term, ‘n’ is the total number of terms and ‘d’ is the common difference.

Calculation:

Let the first term is ‘a’ and common difference is ‘d’.

From the question

a + Tn = 51

⇒ a + a + (n – 1)d = 51

⇒ 2a + (n – 1)d = 51     -----(1)

Second last term = 42

T(n- 1 ) = 42

⇒ a + (n – 2)d = 42     ----(2)

Subtracting equation (2) from (1) we get

a + (n – 1)d – (n – 2)d = 9

⇒ a + nd –d –nd + 2d = 9

⇒ a + d = 9

Second term = a + d = 9

∴ required answer is 9.



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