The mean of six numbers : x - 5, X-1, X, X + 2, X + 4 and x + 12 is 15. Find the mean of first four numbers.
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The mean of six numbers : x - 5, X-1, X, X + 2, X + 4 and x + 12 is 15. Find the mean of first four numbers.
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chemical decomposition produced by passing an electric current through a liquid or solution containing ions.
Answer:
12
Step-by-step explanation:
The mean of six numbers are x – 5, x – 1, x, x + 2, x + 4 and x + 12 is 15
∴ Mean = ((x - 5) + (x – 1) + (x) + (x +2) + (x + 4) + (x + 12))/6
= (x – 5 + x – 1 + x + x + 2 + x + 4 + x + 12)/6
= (12 + 6x)/6 = 15
⇒ 12 + 6x = 90
⇒ 6x = 90 – 12
⇒ 6x = 78
⇒ x = 78/6 = 13
x = 13
∴ The six numbers are (13 – 5), (13 – 1), 13, (13 + 2), (13 + 4), (13 + 12)
i.e. 8, 12, 13, 15, 17, 25
Now, mean of first four numbers = (8 + 12 + 13 + 15)/4 = 48/4 = 12