In one History class of 100 students, 0.25 of the boys and
34 of the girls passed the mock test. A total of 47 students passed the mock test. How many boys failed the History mock test?
| |
Boys |
Girls |
Total |
| Passed the test |
1 u |
3 p |
47 |
| Failed the test |
3 u |
1 p |
53 |
| Total |
4 u |
4 p |
100 |
0.25 of the boys =
14 of the boys
Total number of boys = 4 u
Total number of girls = 4 p
1 u + 3 p = 47 --- (1)
3 u + 1 p = 100 - 47
3 u + 1 p = 53 --- (2)
Make u the same.
(1)
x33 u + 9 p = 141 --- (3)
(3) - (2)
9 p - 1 p = 141 - 53
8 p = 88
1 p = 88 ÷ 8 = 11
From (2)
Number of boys who failed
= 53 - 1 p
= 53 - 11
= 42
Answer(s): 42
