In one Mathematics class of 113 students, 0.1 of the girls and
23 of the boys passed the exam. A total of 30 students passed the exam. How many girls failed the Mathematics exam?
| |
Girls |
Boys |
Total |
| Passed the test |
1 u |
2 p |
30 |
| Failed the test |
9 u |
1 p |
83 |
| Total |
10 u |
3 p |
113 |
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 = 30 --- (1)
9 u + 1 p = 113 - 30
9 u + 1 p = 83 --- (2)
Make u the same.
(1)
x99 u + 18 p = 270 --- (3)
(3) - (2)
18 p - 1 p = 270 - 83
17 p = 187
1 p = 187 ÷ 17 = 11
From (2)
Number of girls who failed
= 83 - 1 p
= 83 - 11
= 72
Answer(s): 72
