The average of 5 numbers is 20 and 4 of the numbers are 10,15,20 and 25. If the numbers are arranged in ascending order, then the average of the last three is
Let the 5th number be x
Given numbers are 10, 15, 20, 25 and
Average of five numbers = 20
$$\therefore \frac{10 + 15 + 20 + 25 + x}{5} = 20$$
70 + x = 100 (or) x = 30
Arranging the numbers in ascending order - 10, 15, 20, 25, 30
Average of last three numbers = $$\frac{20 + 25 + 30}{3}$$
= $$\frac{75}{3}$$ (or) 25
Hence, option A is the correct answer.
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