arrow
arrow
arrow
The mean of 150 items was found to be 45. If at the time of calculation, two items were wrongly taken as 83 and 76 instead of 38 and 46, then the corr
Question

The mean of 150 items was found to be 45. If at the time of calculation, two items were wrongly taken as 83 and 76 instead of 38 and 46, then the correct mean is:

A.

44.5

B.

43.5

C.

43

D.

44

Correct option is A

Given:
Mean of 150 item = 45
Formula Used:
Average =  (Sum of elements)(Number of terms)\frac{\text{ (Sum of elements)}}{\text{(Number of terms)}}​​
Solution:
Incorrect Sum = 150 ×\times​ 45 = 6750
Incorrect Values: 83 and 76
Correct Values: 38 and 46
Calculating the Difference:
Incorrect Sum - Correct Sum = (83+76) - (38+46) = 75
Calculating the Correct Mean:
Correct Sum = Incorrect Sum - Difference = 6750 - 75 = 6675
Correct Mean = Correct Sum  Number of terms \frac{\text{Correct Sum }}{\text{ Number of terms }}​= 6675150\frac{6675}{ 150}​ = 44.5
Correct mean is: 44.5

Free Tests

Free
Must Attempt

CBT-1 Full Mock Test 1

languageIcon English
  • pdpQsnIcon100 Questions
  • pdpsheetsIcon100 Marks
  • timerIcon90 Mins
languageIcon English
Free
Must Attempt

RRB NTPC Graduate Level PYP (Held on 5 Jun 2025 S1)

languageIcon English
  • pdpQsnIcon100 Questions
  • pdpsheetsIcon100 Marks
  • timerIcon90 Mins
languageIcon English
Free
Must Attempt

CBT-1 General Awareness Section Test 1

languageIcon English
  • pdpQsnIcon40 Questions
  • pdpsheetsIcon30 Marks
  • timerIcon25 Mins
languageIcon English
test-prime-package

Access ‘RRB NTPC’ Mock Tests with

  • 60000+ Mocks and Previous Year Papers
  • Unlimited Re-Attempts
  • Personalised Report Card
  • 500% Refund on Final Selection
  • Largest Community
students-icon
354k+ students have already unlocked exclusive benefits with Test Prime!
Our Plans
Monthsup-arrow