In one Science class of 80 students, 0.125 of the boys and
34 of the girls passed the mock test. A total of 40 students passed the mock test. How many boys failed the Science mock test?
|
Boys |
Girls |
Total |
Passed the test |
1 u |
3 p |
40 |
Failed the test |
7 u |
1 p |
40 |
Total |
8 u |
4 p |
80 |
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 = 40 --- (1)
7 u + 1 p = 80 - 40
7 u + 1 p = 40 --- (2)
Make u the same.
(1)
x77 u + 21 p = 280 --- (3)
(3) - (2)
21 p - 1 p = 280 - 40
20 p = 240
1 p = 240 ÷ 20 = 12
From (2)
Number of boys who failed
= 40 - 1 p
= 40 - 12
= 28
Answer(s): 28