If the mean and the standard deviation of the data 3, 5, 7, a ,b are 5 and 2 respectively, then a and b are the roots of the equations:

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Accepted Answer

Correct answer: D. (d) JEE Main 2020 Mean = 3+5+7+a+b5=5 ⇒a+b=10 Variance = 3^2+5^2+7^2+a^2+b^25- (5 )^2=4 ⇒a^2+b^2=62 ⇒(a+b)^2-2 ab=62 ⇒ ab=19 So a and b are the roots of the equation x^2-10x+19=0

$If the mean and the standard deviation of the data 3, 5, 7, a, b are 5 and 2 respectively, then a and b are the roots of the equations:$

Solution

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