JEE Main 2019 — Statistics Question with Solution
From: JEE Main 2019 (Online) 8th April Morning Slot
Question
The mean and variance of seven observations are
8 and 16, respectively. If 5 of the observations are
2, 4, 10, 12, 14, then the product of the remaining
two observations is :
Choose an option
Show full solutionCorrect option: B
Correct answer
B48
Step-by-step explanation
Given mean () = 8
variance () = 16
No of observations (N) = 7
Let the two unknown observation = x and y
We know,
= 16
= 16
x2 + y2 = 100 ........(1)
We know,
= = 8
= 8
x + y = 14 ...........(2)
As (x + y)2 = x2 + y2 + 2xy
(14)2 = 100 + 2xy
196 = 100 + 2xy
xy = 48
variance () = 16
No of observations (N) = 7
Let the two unknown observation = x and y
We know,
= 16
= 16
x2 + y2 = 100 ........(1)
We know,
= = 8
= 8
x + y = 14 ...........(2)
As (x + y)2 = x2 + y2 + 2xy
(14)2 = 100 + 2xy
196 = 100 + 2xy
xy = 48
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This is a previous-year question from JEE Main 2019, covering the Statistics chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.