Question

The class X of Vidyaniketan School has 4 sections- A, B, C, D. The average weights of the students of A, B, C together and A, C, D together are 45 kg and 55 kg resp, while the average weight of the students of A, B, D together and B, C, D together are 50 kg and 60 kg resp. Which of the following could be the average weight of the students of all the four sections together?​
Options are:
A. 47.6
B. 49.9
C. 53.7
D. 56.5

Answer 1

Answer:

52.5

Step-by-step explanation:

A+B+C=45

A+C+D=55

A+B+D=50

B+C+D=60

A+B+C=45

- A+B+D=55

__________

C-D= —5

__________

That' Means A Group = 135

B Group = 165

C Group = 150

D Group = 180

So D Is Greater Than C

And C Is Greater Than A

And C Is Greater Than B

Now Let's See What Is In First Group . They Are 3 Members

They Are A , B , C

Now Again Let's See Second Group . They Are 3 Members

They are A, C , D

NOW What Is Different In Two Groups They Are Common A And C Now We Have Two Different Are B And D Now We Can Clarify The Real Value Of B And D

Now Two Groups Average Weight = 45 And 55 So It Can Called As 135 Kg Of 3 Members In First Group

Now Called As 165 KG of 3 Members In Second Group

So They are Different So D Is 30Kgs Greater Than B

Now Respectly D= B + 30 Kgs

Now Let's Find Out C

Now Another Two Groups Weight = 50 And 60 So It Can Called As 150 Kgs Of 3 Members In Third Group

Now Called As 180Kgs Of 3 Members In Fourth Group

So They Are Different So C Is 30 Kgs Greater Than A

Now Respectly D= B + 30 Kgs

C= A + 30 Kgs

Now Second And Fourth Group Weight = 55 And 60 So It Can Called As 165 Kgs Of 3 Members In Second Group

Now Called As 180 Kgs Of 3 Members In Fourth Group

So They Are Different So B Is 15Kgs Greater Than A

Now Respectly D= B + 30Kgs

C= A + 30Kgs

B= A + 15Kgs

So D = A + 45 Kgs

Now We Have To Add All The Group's = 130+165+150+180 = 630

So We Have To Remove 75 Kgs From 630 Because It's Makes All Equal = 630-90= 540 . Now We Have To Divide With 4 = 540/4 = 135 Now A+B+C = 135 Then = 135 - 45 = 90 / 3 = 30 So A = 30

B = 30+15 = 45

C = 30+ 30 = 60

D = 30+ 45 = 75

Now We Have To Add It All = 210/4 = 52.5