JEE Main 2018MathematicsStatisticsEasyMCQ

JEE Main 2018 — Statistics Question with Solution

JEE Main 2018 (15 Apr)

Question

The mean of a set of 30 observation is 75. If each observations is multiplied by non-zero number λ and then each of them is decreased by 25, their mean remains the same. Then, λ is equal to :

Choose an option

Show full solutionCorrect option: A
Correct answer
A43

Step-by-step explanation

Let 30 observations be x1,  x2, .....…, x30.

Given mean =75

⇒x1+ x2+…+x30=75×30

Now according to question,

λ(x1+ x2+…+x30)-25×3030=75×3030

⇒λ75×30=100×30

⇒λ=43

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About this question

This is a previous-year question from JEE Main 2018, 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.