In one Mathematics class of 120 pupils, 0.25 of the girls and
23 of the boys passed the exam. A total of 50 pupils passed the exam. How many girls failed the Mathematics exam?
|
Girls |
Boys |
Total |
Passed the test |
1 u |
2 p |
50 |
Failed the test |
3 u |
1 p |
70 |
Total |
4 u |
3 p |
120 |
0.25 of the girls =
14 of the girls
Total number of girls = 4 u
Total number of boys = 3 p
1 u + 2 p = 50 --- (1)
3 u + 1 p = 120 - 50
3 u + 1 p = 70 --- (2)
Make u the same.
(1)
x33 u + 6 p = 150 --- (3)
(3) - (2)
6 p - 1 p = 150 - 70
5 p = 80
1 p = 80 ÷ 5 = 16
From (2)
Number of girls who failed
= 70 - 1 p
= 70 - 16
= 54
Answer(s): 54