Question

The sum of art arithmetic sequence 51+52+53+..... +70​

Answer 1

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Given :-

Arithmetic sequence 51+52+53+..... +70

To Find :-

Sum of arithmetic sequence

Solution:-

Step 1 :-

Address the formula, input parameters & values.

Input parameters & values:

The number series 50, 51, 52, 53, . . . . , 69, 70.

The first term a = 50

The common difference d = 1

Total Number of terms n = 21

Step 2:-

apply the input parameter values in the formula

= n/2 x (a + Tn)

$Sum = \frac{n}{2} \times (a + Tn)$

$= \frac{21}{2} \times 50 + 70$

$= \frac{21 \times 120}{2}$

So,

50 + 51 + 52 + 53 + . . . . + 69 + 70 = 1260

Therefore, 1260 is the sum of positive integers between 50 and 21.