Aptitude - Average - Discussion

Discussion Forum : Average - General Questions (Q.No. 14)
14.
If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is:
53.33
54.68
55
None of these
Answer: Option
Explanation:
Required average
= 55 x 50 + 60 x 55 + 45 x 60
55 + 60 + 45
= 2750 + 3300 + 2700
160
= 8750
160
= 54.68
Discussion:
21 comments Page 1 of 3.

Muneer.s said:   1 decade ago
Total marks of first batch(55) is= 55*50=2750
Total marks of second batch (60)is= 60*55=3300
Total marks of third batch(45)= 45*60=2700

Total marks of second batch= 2750+3300+2700 = 8750
Total number of Students= 55+60+45 =160
Avg= 8750/160= 54.68

Madan said:   1 decade ago
Average of Batch A = 55+60+45 = 160.
Average of Batch B = 50+55+60 = 165.

Average marks of all the students is = 160+165/6.

S.Balasubramaniam said:   1 decade ago
Average of batch A & B = 55*50+60*55+45*60/55+60+45.

Total average number of batch = 8750/160.

Total average = 54.68.
(1)

Swordist said:   1 decade ago
Total marks of first batch(55) is = 55*50 = 2750.
Total marks of second batch (60)is = 60*55 = 3300.
Total marks of third batch(45) = 45*60 = 2700.

Total marks of second batch = 2750+3300+2700 = 8750.
Total number of Students = 55+60+45 = 160.
Avg = 8750/160 = 54.6875 = 54.69.

Answer: D.

Vicky said:   9 years ago
Thanks, @Balasubramaniam.

Riyaz said:   9 years ago
Thank you all who has given suggestions while solving the problems.

Bhavik oza said:   9 years ago
Average marks are asked. So how can 160 come in the denominator? If you keep 160 then you will get average students as your answer.

Sadhya said:   8 years ago
I tell trick here given students 55 60 45 . avg marks 50 55 60. let assume average as 50. first 55 students.

avg 50 given ok.but in case of next 60 members avg 55 given that means 60*5 = 300 extra .in case of remaining 45 students given 60 .that means 45*10 = 450 extra.totally 300 + 450 = 750 extra.

750 extra on 160 students so 750/160 = 4.68.finally 50 + 4.68 = 54.68 answer.
(1)

Keshav singh said:   8 years ago
Thanks @S. Balasubramaniam.

Swa said:   7 years ago
Thank you @Sadhya.


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