56 students from Class E and Class F took a Mathematics test. The average marks of the students was 78 marks. The average marks of the students in Class E was 82 marks and the average marks of the students in Class F was 75 marks. How many students were there in Class E?
Students in
Class E |
Total scores in
Class E |
Students in
Class F |
Total scores in
Class F |
Total scores of
Class E and Class F |
56
|
56 x 82 =
4592 |
0
|
0
|
4592
|
55
|
55 x 82 =
4510 |
1
|
1 x 75 =
75 |
4585
|
24
|
24 x 82 =
1968 |
32
|
32 x 75 =
2400 |
4368
|
Total scores of Class F and Class E
= 56 x 78
= 4368
If all the students are in Class E,
total scores
= 56 x 82
= 4592
Big difference
= 4592 - 4368
= 224
Small difference
= 82 - 75
= 7
Number of students in Class F
= 224 ÷ 7
= 32
Number of students in Class E
= 56 - 32
= 24
Answer(s): 24
