Question

The first and the last terms of an AP are 7 and 55 respectively. the sum of 10th element from the beginning and 10th element from the end is

Answer 1

Step-by-step explanation:

I hope this will help you

Answer 2

Answer:

62

Step-by-step explanation:

Given:-  First term = 7, last term = 55.

To Find:- Sum of 10th element from beginning and 10th element from the

               end.

Solution:-

As we know, last term = first term + (n - 1) d

where n = number of terms, d = common difference.

∴ 55 = 7 + (n - 1) d

⇒ (n - 1)d = 55 - 7

⇒ d = $\frac{48}{(n - 1)}$

10th term from beginning will be,

$T_{10} = a + (10 - 1)d$

     = 7 + 9d

     = 7 + 9 × $\frac{48}{(10 - 1)}$

     = 7 + 9 × $\frac{48}{9}$

     = 7 + 48

     = 55.

As the 10th term from beginning = 55

Therefore, 10th term from the end will be 7.

Hence, the sum of 10th element from the beginning and 10th element from the end is (55 + 7) = 62.

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