In one Science class of 88 pupils, 0.25 of the girls and
78 of the boys passed the mock test. A total of 57 pupils passed the mock test. How many girls failed the Science mock test?
| |
Girls |
Boys |
Total |
| Passed the test |
1 u |
7 p |
57 |
| Failed the test |
3 u |
1 p |
31 |
| Total |
4 u |
8 p |
88 |
0.25 of the girls =
14 of the girls
Total number of girls = 4 u
Total number of boys = 8 p
1 u + 7 p = 57 --- (1)
3 u + 1 p = 88 - 57
3 u + 1 p = 31 --- (2)
Make u the same.
(1)
x33 u + 21 p = 171 --- (3)
(3) - (2)
21 p - 1 p = 171 - 31
20 p = 140
1 p = 140 ÷ 20 = 7
From (2)
Number of girls who failed
= 31 - 1 p
= 31 - 7
= 24
Answer(s): 24
