जॉइन Examsbookउत्तर : 2. "900/19 %"
Find by how much percentage the average of first 10 odd numbers (starting from 1) is greater than the last term ?5
प्र: Find by how much percentage the average of first 10 odd numbers (starting from 1) is greater than the last term ?
- 1991/16 %false
- 2900/19 %true
- 3874/13 %false
- 4719/17 %false
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उत्तर : 2. "900/19 %"
व्याख्या :
Answer: B) 900/19 % Explanation: First ten odd numbers form an arithmetic progression of the form1,3,5,7,9......here a = first term = 1d = common difference = 2Average of first n numbers = (2a + (n - 1)d)/2n th term of the AP = a + (n - 1)dSubstituting a = 1, d = 2 and n = 10 in the above formulas average of first 10 numbers = 1010 th term of the AP = 19Therefore average of first 10 terms is 19 - 10 = 9 greater thanthe last term. Hence the average is greater than the sum by9/19 X 100 = 900/19 %