In one Social Studies class of 108 pupils, 0.125 of the boys and
34 of the girls passed the exam. A total of 46 pupils passed the exam. How many boys failed the Social Studies exam?
| |
Boys |
Girls |
Total |
| Passed the test |
1 u |
3 p |
46 |
| Failed the test |
7 u |
1 p |
62 |
| Total |
8 u |
4 p |
108 |
0.125 of the boys =
18 of the boys
Total number of boys = 8 u
Total number of girls = 4 p
1 u + 3 p = 46 --- (1)
7 u + 1 p = 108 - 46
7 u + 1 p = 62 --- (2)
Make u the same.
(1)
x77 u + 21 p = 322 --- (3)
(3) - (2)
21 p - 1 p = 322 - 62
20 p = 260
1 p = 260 ÷ 20 = 13
From (2)
Number of boys who failed
= 62 - 1 p
= 62 - 13
= 49
Answer(s): 49
