In one Mathematics class of 105 pupils, 0.25 of the girls and
23 of the boys passed the mock exam. A total of 30 pupils passed the mock exam. How many girls failed the Mathematics mock exam?
| |
Girls |
Boys |
Total |
| Passed the test |
1 u |
2 p |
30 |
| Failed the test |
3 u |
1 p |
75 |
| Total |
4 u |
3 p |
105 |
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 = 30 --- (1)
3 u + 1 p = 105 - 30
3 u + 1 p = 75 --- (2)
Make u the same.
(1)
x33 u + 6 p = 90 --- (3)
(3) - (2)
6 p - 1 p = 90 - 75
5 p = 15
1 p = 15 ÷ 5 = 3
From (2)
Number of girls who failed
= 75 - 1 p
= 75 - 3
= 72
Answer(s): 72
