In one Social Studies class of 105 pupils, 0.1 of the girls and
23 of the boys passed the test. A total of 36 pupils passed the test. How many girls failed the Social Studies test?
|
Girls |
Boys |
Total |
Passed the test |
1 u |
2 p |
36 |
Failed the test |
9 u |
1 p |
69 |
Total |
10 u |
3 p |
105 |
0.1 of the girls =
110 of the girls
Total number of girls = 10 u
Total number of boys = 3 p
1 u + 2 p = 36 --- (1)
9 u + 1 p = 105 - 36
9 u + 1 p = 69 --- (2)
Make u the same.
(1)
x99 u + 18 p = 324 --- (3)
(3) - (2)
18 p - 1 p = 324 - 69
17 p = 255
1 p = 255 ÷ 17 = 15
From (2)
Number of girls who failed
= 69 - 1 p
= 69 - 15
= 54
Answer(s): 54