Average of 50 numbers was calculated as 20 when three numbers, 26, 36 and 64 were wrongly read as 31, 46 and 59 respectively. What is the correct average?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 19.8
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Understanding |
Application |
Calculation |
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3 numbers, 26, 36 and 64 were wrongly read as 31, 46 and 59 respectively. |
Net difference in the sum of numbers = -10 That means actual sum is 10 less than given. |
⇒ [26 – 31] + [36 – 46] + [64 – 59] ⇒ -5 – 10 + 5 ⇒ -10 |
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Since the sum is less than given, average will also be less. |
Difference in Average of 50 numbers = -0.5 |
⇒ -10/50 = -0.2 |
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Hence, Actual average = 19.8 |
⇒ 20 – 0.2 = 19.8 |