70 students from Class G and Class H took a Mathematics test. The average marks of the students was 86 marks. The average marks of the students in Class G was 91 marks and the average marks of the students in Class H was 77 marks. How many students were there in Class G?
Students in
Class G |
Total scores in
Class G |
Students in
Class H |
Total scores in
Class H |
Total scores of
Class G and Class H |
70
|
70 x 91 =
6370 |
0
|
0
|
6370
|
69
|
69 x 91 =
6279 |
1
|
1 x 77 =
77 |
6356
|
45
|
45 x 91 =
4095 |
25
|
25 x 77 =
1925 |
6020
|
Total scores of Class H and Class G
= 70 x 86
= 6020
If all the students are in Class G,
total scores
= 70 x 91
= 6370
Big difference
= 6370 - 6020
= 350
Small difference
= 91 - 77
= 14
Number of students in Class H
= 350 ÷ 14
= 25
Number of students in Class G
= 70 - 25
= 45
Answer(s): 45
