In one Science class of 110 pupils, 0.25 of the boys and
23 of the girls passed the mock exam. A total of 40 pupils passed the mock exam. How many boys failed the Science mock exam?
| |
Boys |
Girls |
Total |
| Passed the test |
1 u |
2 p |
40 |
| Failed the test |
3 u |
1 p |
70 |
| Total |
4 u |
3 p |
110 |
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 = 40 --- (1)
3 u + 1 p = 110 - 40
3 u + 1 p = 70 --- (2)
Make u the same.
(1)
x33 u + 6 p = 120 --- (3)
(3) - (2)
6 p - 1 p = 120 - 70
5 p = 50
1 p = 50 ÷ 5 = 10
From (2)
Number of boys who failed
= 70 - 1 p
= 70 - 10
= 60
Answer(s): 60
