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Bunuel
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The average (arithmetic mean) of 20 numbers is 30, and the average (ar 22 Mar 2019, 00:56
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B
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85% (01:03) correct 15% (01:15) wrong based on 61 sessions

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The average (arithmetic mean) of 20 numbers is 30, and the average (arithmetic mean) of 30 other numbers is 20. What is the average of all 50 numbers?

(A) 23
(B) 24
(C) 25
(D) 26
(E) 27
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B
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The average (arithmetic mean) of 20 numbers is 30, and the average (ar 22 Mar 2019, 04:02
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Bunuel
The average (arithmetic mean) of 20 numbers is 30, and the average (arithmetic mean) of 30 other numbers is 20. What is the average of all 50 numbers?

(A) 23
(B) 24
(C) 25
(D) 26
(E) 27
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sum of 20 no = 600
and sum of 30 o = 600
so
1200/50 = 24
IMO B
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The average (arithmetic mean) of 20 numbers is 30, and the average (ar 24 Mar 2019, 18:35
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Bunuel
The average (arithmetic mean) of 20 numbers is 30, and the average (arithmetic mean) of 30 other numbers is 20. What is the average of all 50 numbers?

(A) 23
(B) 24
(C) 25
(D) 26
(E) 27
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Average = (20 x 30 + 30 x 20)/50

Average = 1200/50

Average = 24

Answer: B
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The average (arithmetic mean) of 20 numbers is 30, and the average (ar 24 Mar 2019, 18:42
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30(2/5) +20(3/5)=24
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The average (arithmetic mean) of 20 numbers is 30, and the average (ar Updated on: 03 Aug 2022, 20:29
Originally posted by BrushMyQuant on 01 Aug 2022, 02:45.
Last edited by BrushMyQuant on 03 Aug 2022, 20:29, edited 1 time in total.
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Theory

    ➡ Average = Sum of all the Values / Total Number of Values
    ➡ Sum of All the values = Average * Total Number of Values

The average (arithmetic mean) of 20 numbers is 30

Sum of 20 numbers = Average * 20 = 30 * 20 = 600

The average (arithmetic mean) of 30 other numbers is 20

Sum of 30 numbers = Average * 30 = 20*30 = 600

The average of all 50 numbers

Average = Sum of all the Values / 50 = (Sum of 20 numbers + Sum of 30 numbers) / 50 = \(\frac{600 + 600 }{ 50}\)
= \(\frac{1200}{50}\) = 24

So, Answer will be B.
Hope it helps!

Watch the following video to Learn the Basics of Statistics

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The average (arithmetic mean) of 20 numbers is 30, and the average (ar 01 Aug 2022, 05:11
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Total marks of 20 numbers with an average of 30 = 20*30 = 600

Total marks of 30 numbers with an average of 20 = 30*20 = 600

Thus, total marks of 50 students = 600 + 600 = 1200

Thus, average of 50 students = 1200/50 = 24

Thus, the correct option is B.
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The average (arithmetic mean) of 20 numbers is 30, and the average (ar 01 Aug 2022, 10:20
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Bunuel
The average (arithmetic mean) of 20 numbers is 30, and the average (arithmetic mean) of 30 other numbers is 20. What is the average of all 50 numbers?

(A) 23
(B) 24
(C) 25
(D) 26
(E) 27
Show more
\(\frac{20*30 + 30*20}{(20+30)}= \frac{1200}{50} =>24\), Answer must be (B)
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