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Question
The mean of 18, 24, 15, 2x + 1 and 12 is 21. Find the value of x.
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Solution
Mean of given data = `(18 + 24 + 15 + 2x + 1 + 12)/(5)`
⇒ 21 = `(70 + 2x) / (5)`
⇒ 5 × 21 = 70 + 2x
⇒ 105 = 70 + 2x
⇒ 2x = 105 - 70
⇒ 2x = 35
⇒ x = `35/2`
⇒ x = 17.5
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