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The average of a set of 5 numbers is 20. If 4 additional numbers are added to the set, the average increases to 24. What is the average of the additional 4 numbers?
A. 22
B. 25
C. 26
D. 28
E. 29
OA E
The average of a set of 5 numbers is 20. If 4 additional numbers are added to the set, the average...
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Let N be the Total of 5 Nos. Thus, the average will be N/5=20. So, N=100
let x'be the sum of 4 additional numbers. The new avg = (n+x')/5+4=24. So, N+X'= 216
From the above, X'=116. This X' is the sum of 4 new numbers. The avg = 116/4=29
let x'be the sum of 4 additional numbers. The new avg = (n+x')/5+4=24. So, N+X'= 216
From the above, X'=116. This X' is the sum of 4 new numbers. The avg = 116/4=29
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Solution:
Using the average formula: average = sum/number, we know the initial sum is 5 x 20 = 100. We can let x = the sum of the additional 4 numbers and create the equation:
(100 + x)/(5 + 4) = 24
(100 + x)/9 = 24
100 + x = 216
x = 116
The average of the 4 numbers is 116/4 = 29.
Answer: E
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