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Find the sum of last ten terms of the AP: 8, 10, 12,---, 126

Solution:

Given, the series in AP as 8, 10, 12, ………, 126.

We have to find the sum of the last 10 terms of the series.

From the series,

We need to find the sum of last 10 terms,

So, common difference, d = 8 -10 = -2

so we take the first term (a) as 126.

The sum of the first n terms of an AP is given by

Sₙ = n/2[2a + (n-1)d]

So, S₁₀ = 10/2[2(126) + (10 - 1)(-2)]

= 5[252 + 9(-2)]

= 5[252 - 18]

= 5[234]

= 1170

Therefore, the sum of the last 10 terms of an AP is 1170.

✦ Try This: Find the sum of the last ten terms of the AP: 125, 120, 115,..........,15

☛ Also Check: NCERT Solutions for Class 10 Maths Chapter 5

NCERT Exemplar Class 10 Maths Exercise 5.3 Problem 30

Find the sum of last ten terms of the AP: 8, 10, 12,---, 126

Summary:

An arithmetic progression (AP) is a sequence where the differences between every two consecutive terms are the same. The sum of the last ten terms of the AP: 8, 10, 12,---, 126 is 1170

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