In one History class of 97 students, 0.1 of the girls and
23 of the boys passed the test. A total of 42 students passed the test. How many girls failed the History test?
| |
Girls |
Boys |
Total |
| Passed the test |
1 u |
2 p |
42 |
| Failed the test |
9 u |
1 p |
55 |
| Total |
10 u |
3 p |
97 |
0.1 of the girls =
110 of the girls
Total number of girls = 10 u
Total number of boys = 3 p
1 u + 2 p = 42 --- (1)
9 u + 1 p = 97 - 42
9 u + 1 p = 55 --- (2)
Make u the same.
(1)
x99 u + 18 p = 378 --- (3)
(3) - (2)
18 p - 1 p = 378 - 55
17 p = 323
1 p = 323 ÷ 17 = 19
From (2)
Number of girls who failed
= 55 - 1 p
= 55 - 19
= 36
Answer(s): 36
