In one Social Studies class of 114 students, 0.1 of the boys and
34 of the girls passed the mock exam. A total of 40 students passed the mock exam. How many boys failed the Social Studies mock exam?
| |
Boys |
Girls |
Total |
| Passed the test |
1 u |
3 p |
40 |
| Failed the test |
9 u |
1 p |
74 |
| Total |
10 u |
4 p |
114 |
0.1 of the boys =
110 of the boys
Total number of boys = 10 u
Total number of girls = 4 p
1 u + 3 p = 40 --- (1)
9 u + 1 p = 114 - 40
9 u + 1 p = 74 --- (2)
Make u the same.
(1)
x99 u + 27 p = 360 --- (3)
(3) - (2)
27 p - 1 p = 360 - 74
26 p = 286
1 p = 286 ÷ 26 = 11
From (2)
Number of boys who failed
= 74 - 1 p
= 74 - 11
= 63
Answer(s): 63
