63 students from Class L and Class M took a Mathematics test. The average marks of the students was 91 marks. The average marks of the students in Class L was 96 marks and the average marks of the students in Class M was 81 marks. How many students were there in Class L?
Students in
Class L |
Total scores in
Class L |
Students in
Class M |
Total scores in
Class M |
Total scores of
Class L and Class M |
63
|
63 x 96 =
6048 |
0
|
0
|
6048
|
62
|
62 x 96 =
5952 |
1
|
1 x 81 =
81 |
6033
|
42
|
42 x 96 =
4032 |
21
|
21 x 81 =
1701 |
5733
|
Total scores of Class M and Class L
= 63 x 91
= 5733
If all the students are in Class L,
total scores
= 63 x 96
= 6048
Big difference
= 6048 - 5733
= 315
Small difference
= 96 - 81
= 15
Number of students in Class M
= 315 ÷ 15
= 21
Number of students in Class L
= 63 - 21
= 42
Answer(s): 42
