Consider a set of n observations x1,x2,x3...xnwith mean x¯. If xi is increased by i , for each i , then the mean x¯ is increased by 10. If xi is decreased by i , then the mean is decreased by 5, then a possible value of ‘n’ is

Mean=∑i=1nxin=x¯⇒∑i=1nxi=nx¯ Given ∑i=1nxi+in=x¯+10→(1) and ∑i=1nxi-in=x¯-5→(2) (1) -(2)⇒2∑i=1ni=15n⇒2 nn+12=15n⇒ n=14

Consider a set of n observations x1,x2,x3...xnwith mean x¯. If xi is increased by i , for each i , then the mean x¯ is increased by 10. If xi is decreased by i , then the mean is decreased by 5, then a possible value of ‘n’ is

Mean=∑i=1nxin=x¯⇒∑i=1nxi=nx¯ Given ∑i=1nxi+in=x¯+10→(1) and ∑i=1nxi-in=x¯-5→(2) (1) -(2)⇒2∑i=1ni=15n⇒2 nn+12=15n⇒ n=14

AI Mentor

Check Your IQ

Free Expert Demo

Try Test

Courses

Dropper NEET Course Dropper JEE Course Class - 12 NEET Course Class - 12 JEE Course Class - 11 NEET Course Class - 11 JEE Course Class - 10 Foundation NEET Course Class - 10 Foundation JEE Course Class - 10 CBSE Course Class - 9 Foundation NEET Course Class - 9 Foundation JEE Course Class -9 CBSE Course Class - 8 CBSE Course Class - 7 CBSE Course Class - 6 CBSE Course

Offline Centres

Consider a set of n observations $x_{1}, x_{2}, x_{3} ... x_{n}$ with mean $\bar{x}$ . If $x_{i}$ is increased by i , for each i , then the mean $\bar{x}$ is increased by 10. If $x_{i}$ is decreased by i , then the mean is decreased by 5, then a possible value of ‘n’ is

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

answer is B.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

$M e a n = \frac{\sum_{i = 1}^{n} x_{i}}{n} = \bar{x} \Rightarrow \sum_{i = 1}^{n} x_{i} = n \bar{x}$

$Given \frac{\sum_{i = 1}^{n} (x_{i} + i)}{n} = \bar{x} + 10 \to (1)$

$and \frac{\sum_{i = 1}^{n} (x_{i} - i)}{n} = \bar{x} - 5 \to (2)$

$(1) - (2) \Rightarrow 2 \sum_{i = 1}^{n} i = 15 n \Rightarrow \frac{2 n (n + 1)}{2} = 15 n \Rightarrow n = 14$

Watch 3-min video & get full concept clarity

courses

No courses found

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Online Course for IIT JEE

Best Online Course for NEET

Best Online Course for CBSE

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Get Expert Academic Guidance – Connect with a Counselor Today!

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Online Course for IIT JEE

Best Online Course for NEET

Best Online Course for CBSE

best study material, now at your finger tips!

live classes
progress tracking
24x7 mentored guidance
study plan analysis

download the app

Consider a set of n observations x1,x2,x3...xnwith mean x¯. If xi is increased by i , for each i , then the mean x¯ is increased by 10. If xi is decreased by i , then the mean is decreased by 5, then a possible value of ‘n’ is

Best Courses for You

Detailed Solution

courses

Get Expert Academic Guidance – Connect with a Counselor Today!

best study material, now at your finger tips!

download the app

Download the App

Consider a set of n observations $x_{1}, x_{2}, x_{3} ... x_{n}$ with mean $\bar{x}$ . If $x_{i}$ is increased by i , for each i , then the mean $\bar{x}$ is increased by 10. If $x_{i}$ is decreased by i , then the mean is decreased by 5, then a possible value of ‘n’ is