Question

Arithmetic mean of marks out of 25 Scored by 10 students was 15 ohe of the of the student named karishma enduired the other 9 students and the deviations from her marks are noted 8,6,3,10,2,3,4,6,find karishma s marks​

Answer 1

Answer:

15.3

Explanation:

Given that

Arithmetic mean of marks (out of 25) scored by )10 students was 15

The deviations from karisma’s marks of other 9 students are noted as -8,-6,-3,-1,0,2,3,4,6.

Need to find karishma’s marks

Let assume mark of karisma = x

So marks of each student = marks of karishma + deviation of their marks from karisma mark

So marks of remaining 9 students will be x – 8, x – 6 , x – 3 , x – 1 , x – 0 , x +2 , x + 3 , x + 4 , x + 6

So total mark of 10 students = marks of karishma + marks of remaining 9 students

total mark of 10 students = x + x – 8+ x – 6 + x – 3 + x – 1 + x – 0 + x +2 + x + 3 + x + 4 + x + 6

total mark of 10 students = 10x - 3

Number of students = 10

\text{ Arithmetic mean of 10 students } =\frac{\text { total marks of 10 students }}{\text { number of students }}

\begin{aligned}&\Rightarrow 15=\frac{10 x-3}{10}\\\\&\Rightarrow 150+3=10 x\\\\&\Rightarrow 153=10 x\\\\&\Rightarrow x=\frac{153}{10}=15.3\end{aligned}

Hence marks of Karishma = x = 15.3