In one Science class of 100 students, 0.25 of the boys and
78 of the girls passed the exam. A total of 65 students passed the exam. How many boys failed the Science exam?
| |
Boys |
Girls |
Total |
| Passed the test |
1 u |
7 p |
65 |
| Failed the test |
3 u |
1 p |
35 |
| Total |
4 u |
8 p |
100 |
0.25 of the boys =
14 of the boys
Total number of boys = 4 u
Total number of girls = 8 p
1 u + 7 p = 65 --- (1)
3 u + 1 p = 100 - 65
3 u + 1 p = 35 --- (2)
Make u the same.
(1)
x33 u + 21 p = 195 --- (3)
(3) - (2)
21 p - 1 p = 195 - 35
20 p = 160
1 p = 160 ÷ 20 = 8
From (2)
Number of boys who failed
= 35 - 1 p
= 35 - 8
= 27
Answer(s): 27
