135 students went for a spelling test and 42 of them achieved Bronze certificates.
25 of the boys and
14 of the girls achieved Bronze certificates. How many boys did not achieve Bronze certificates?
| Girls |
Boys |
| 5 u |
4 p |
Achieved
Bronze |
Did not achieve
Bronze |
Achieved
Bronze |
Did not achieve
Bronze |
| 2 u |
3 u |
1 p |
3 p |
Number of students who did not achieve Bronze certificates
= 135 - 42
= 93
2 u + 1 p = 42
1 p = 42 - 2 u --- (1)
3 u + 3 p = 93
3 p = 93 - 3 u --- (2)
Make p the same.
(1)
x33 p = 126 - 6 u --- (3)
(2) = (3)
93 - 3 u = 126 - 6 u
6 u - 3 u = 126 - 93
3 u = 33
1 u = 33 ÷ 3 = 11
Number of girls who achieved Bronze certificates
= 2 u
= 2 x 11
= 22
Number of boys who achieved Bronze certificates
= 42 - 22
= 20
Answer(s): 20
