Question

find the sum of all 2 digit odd positive numbers​

Answer 1

Answer:

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Step-by-step explanation:

Two digit odd positive numbers are 11, 13, 15, ...., 99.

This is an A.P. with,

First term, a = 11, Common difference, d = 13 - 11 = 2, and last term, an = 99

Now, an = a + (n - 1)d

99 = 11 + (n - 1)2

99 = 11 + 2n - 2

rightwards double arrow99 = 9 + 2n

2n = 90

n = 45

begin mathsize 12px style straight S subscript straight n space equals space straight n over 2 open parentheses straight a space plus space straight l close parentheses space equals space 45 over 2 open parentheses 11 plus 99 close parentheses space equals space 45 over 2 cross times 110 space equals space 2475 end style

Thus, the sum of all two-digit odd positive numbers is 2475.

Answer 2

Answer:

Step-by-step explanation:

Answer : 2475

This are the following steps