In one Science class of 120 pupils, 0.125 of the girls and
34 of the boys passed the exam. A total of 60 pupils passed the exam. How many girls failed the Science exam?
| |
Girls |
Boys |
Total |
| Passed the test |
1 u |
3 p |
60 |
| Failed the test |
7 u |
1 p |
60 |
| Total |
8 u |
4 p |
120 |
0.125 of the girls =
18 of the girls
Total number of girls = 8 u
Total number of boys = 4 p
1 u + 3 p = 60 --- (1)
7 u + 1 p = 120 - 60
7 u + 1 p = 60 --- (2)
Make u the same.
(1)
x77 u + 21 p = 420 --- (3)
(3) - (2)
21 p - 1 p = 420 - 60
20 p = 360
1 p = 360 ÷ 20 = 18
From (2)
Number of girls who failed
= 60 - 1 p
= 60 - 18
= 42
Answer(s): 42
