The average of nine consecutive numbers is n . If the next two numbers are…
2022
The average of nine consecutive numbers is n . If the next two numbers are also included, the new average is:
- A.
remain the same
- B.
increase by 1
- C.
increase by 1.5
- D.
increase by 2
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Correct answer: B
Let the nine consecutive numbers be x, x+1, x+2, ..., x+8. Their sum is:
Sum = x + (x+1) + (x+2) + ... + (x+8) = 9x + (1+2+...+8) = 9x + 36.
Average of these nine numbers = (9x + 36)/9 = x + 4. Given that this average is n, so n = x + 4.
The next two numbers are x+9 and x+10. Their sum is:
Sum = (x+9) + (x+10) = 2x + 19.
New total sum = (9x + 36) + (2x + 19) = 11x + 55.
New average = (11x + 55)/11 = x + 5.
Since n = x + 4, the new average = (x + 4) + 1 = n + 1.
Therefore, the new average increases by 1.
हिन्दी उत्तर:
मान लीजिए कि नौ क्रमिक संख्याएँ x, x+1, x+2, ..., x+8 हैं। उनका योग है:
योग = x + (x+1) + (x+2) + ... + (x+8) = 9x + (1+2+...+8) = 9x + 36।
इन नौ संख्याओं का औसत = (9x + 36)/9 = x + 4। दिया गया है कि यह औसत n है, इसलिए n = x + 4।
अगली दो संख्याएँ x+9 और x+10 हैं। उनका योग है:
योग = (x+9) + (x+10) = 2x + 19।
नया कुल योग = (9x + 36) + (2x + 19) = 11x + 55।
नया औसत = (11x + 55)/11 = x + 5।
चूँकि n = x + 4, नया औसत = (x + 4) + 1 = n + 1।
इसलिए, नया औसत 1 बढ़ता है।