56 students from Class F and Class G took a Mathematics test. The average marks of the students was 79 marks. The average marks of the students in Class F was 84 marks and the average marks of the students in Class G was 70 marks. How many students were there in Class F?
Students in Class F |
Total scores in Class F |
Students in Class G |
Total scores in Class G |
Total scores of Class F and Class G |
56
|
56 x 84 = 4704 |
0
|
0
|
4704
|
55
|
55 x 84 = 4620 |
1
|
1 x 70 = 70 |
4690
|
36
|
36 x 84 = 3024 |
20
|
20 x 70 = 1400 |
4424
|
Total scores of Class G and Class F
= 56 x 79
= 4424
If all the students are in Class F,
total scores
= 56 x 84
= 4704
Big difference
= 4704 - 4424
= 280
Small difference
= 84 - 70
= 14
Number of students in Class G
= 280 ÷ 14
= 20
Number of students in Class F
= 56 - 20
= 36
Answer(s): 36