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Weighted average of two groups

1000BeginnerStatisticsAlgebra

AMC 10A · 2005 · Problem 6

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

Answer choices

A
23
B
24
C
25
D
26
E
27
0 students attempted0% solvedRating 1000

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