In one History class of 118 pupils, 0.25 of the boys and
23 of the girls passed the exam. A total of 57 pupils passed the exam. How many boys failed the History exam?
| |
Boys |
Girls |
Total |
| Passed the test |
1 u |
2 p |
57 |
| Failed the test |
3 u |
1 p |
61 |
| Total |
4 u |
3 p |
118 |
0.25 of the boys =
14 of the boys
Total number of boys = 4 u
Total number of girls = 3 p
1 u + 2 p = 57 --- (1)
3 u + 1 p = 118 - 57
3 u + 1 p = 61 --- (2)
Make u the same.
(1)
x33 u + 6 p = 171 --- (3)
(3) - (2)
6 p - 1 p = 171 - 61
5 p = 110
1 p = 110 ÷ 5 = 22
From (2)
Number of boys who failed
= 61 - 1 p
= 61 - 22
= 39
Answer(s): 39
