65 students from Class X and Class Y took a Mathematics test. The average marks of the students was 82 marks. The average marks of the students in Class X was 88 marks and the average marks of the students in Class Y was 73 marks. How many students were there in Class X?
Students in
Class X |
Total scores in
Class X |
Students in
Class Y |
Total scores in
Class Y |
Total scores of
Class X and Class Y |
65
|
65 x 88 =
5720 |
0
|
0
|
5720
|
64
|
64 x 88 =
5632 |
1
|
1 x 73 =
73 |
5705
|
39
|
39 x 88 =
3432 |
26
|
26 x 73 =
1898 |
5330
|
Total scores of Class Y and Class X
= 65 x 82
= 5330
If all the students are in Class X,
total scores
= 65 x 88
= 5720
Big difference
= 5720 - 5330
= 390
Small difference
= 88 - 73
= 15
Number of students in Class Y
= 390 ÷ 15
= 26
Number of students in Class X
= 65 - 26
= 39
Answer(s): 39
