69 students from Class N and Class P took a Mathematics test. The average marks of the students was 88 marks. The average marks of the students in Class N was 93 marks and the average marks of the students in Class P was 78 marks. How many students were there in Class N?
Students in
Class N |
Total scores in
Class N |
Students in
Class P |
Total scores in
Class P |
Total scores of
Class N and Class P |
69
|
69 x 93 =
6417 |
0
|
0
|
6417
|
68
|
68 x 93 =
6324 |
1
|
1 x 78 =
78 |
6402
|
46
|
46 x 93 =
4278 |
23
|
23 x 78 =
1794 |
6072
|
Total scores of Class P and Class N
= 69 x 88
= 6072
If all the students are in Class N,
total scores
= 69 x 93
= 6417
Big difference
= 6417 - 6072
= 345
Small difference
= 93 - 78
= 15
Number of students in Class P
= 345 ÷ 15
= 23
Number of students in Class N
= 69 - 23
= 46
Answer(s): 46
