Statistics | Mock Test | Question 13

[Vijender Singh]

Could someone explain Question 13 of mock test? I spend about an hour on it and couldnt get the right answer? :(

Regards

Vijender

[Satya Mohapatra]

[gorthi lakshmisahitya]

Hello

This is Sahitya.Thank you for providing the worked out solution.

But I didn't understand why the dinominator was sum of variables A,B,C,D i.e,their combinations.

Please clarify this. 

[Satya Mohapatra]

Given, Average of sec ABCD is 60, i.e. total marks of section At + Bt+ Ct+  Dt /A+B+C+t =60

that how we calculate mean or average.

--

Satya Mohapatra
Mobile: 9620931608

[Satya Mohapatra]

typo,

Given, Average of sec ABCD is 60, i.e. total marks of section At + Bt+ Ct+  Dt /A+B+C+D =60  

[Vijender Singh]

Thanks for your response @Satya. 

Regards,

Vijender

On Friday, November 13, 2020 at 3:49:28 PM UTC+5:30 Satya Mohapatra wrote:

[Praveenkumar a k]

Did get the answer of Nb = 70.

But was very apprehensive of it as that meant the numbe of students in section A (Na=2/3 * 70) and section C (Nc=5/6 * 70) are non-integer values....:-)

[Malabika Guha Mustafi]

The average marks of all the students of four sections A, B, C, D taken together is 60 while the average marks of students of each sections is 45, 50, 72, and 80 respectively. If the average marks of sections A, and B together is 48 and of B and C together is 60 and the number of students in section D is 35, then find the number of students in section B.

Let, the No .of student in A, B, C sections  are a, b, c respectively.

student in D section =35
45a+50b= 48(a+b)

or, 3a=2b

 50b+72c= 60(b+c)

or, 10b =12c 

or, 5b=6c

now, 60* (a+b+c+35)= 45 a+50b+72c+(80*35)

or, 60a+60b+60c +2100 = 45a+50b+72c + 2800

or, 15a+10b-12c = 700

or, 10b+ 10b- 10b =700 [ replacing a and c with b]

or, 10b=700

or ,b=70

A, C consists fraction number students :)

[ramasubramanian raman]

Dear Sri Satya Mohapatra

 I agree with you. But, as per given data number of students in class c will be 10b/12 which comes to be 700/12 which will be a fraction.

How can there be a a fractional student in that class C?

Can someone explain?

With salutes,

R Raman

On Friday, November 13, 2020 at 3:49:28 PM UTC+5:30 Satya Mohapatra wrote: