What is the average of all natural numbers from 49 to 125?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 87
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Understanding |
Application |
Calculation |
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Sum of AP = n/2 [2a + (n – 1)d] |
Sum of numbers from 49 to 125 (total 77 numbers) = 77 × 87 |
⇒ 77/2 [2 × 49 + (77 – 1) × 1] ⇒ 77/2 [98 + 76] ⇒ 77/2 × 174 ⇒ 77 × 87 |
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So, Average = 87 |
⇒ (77 × 87)/77 ⇒ 87 |