In one Social Studies class of 104 pupils, 0.25 of the boys and
34 of the girls passed the mock test. A total of 64 pupils passed the mock test. How many boys failed the Social Studies mock test?
|
Boys |
Girls |
Total |
Passed the test |
1 u |
3 p |
64 |
Failed the test |
3 u |
1 p |
40 |
Total |
4 u |
4 p |
104 |
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 = 64 --- (1)
3 u + 1 p = 104 - 64
3 u + 1 p = 40 --- (2)
Make u the same.
(1)
x33 u + 9 p = 192 --- (3)
(3) - (2)
9 p - 1 p = 192 - 40
8 p = 152
1 p = 152 ÷ 8 = 19
From (2)
Number of boys who failed
= 40 - 1 p
= 40 - 19
= 21
Answer(s): 21