175 pupils went for a physical fitness test and 58 of them achieved Bronze certificates.
25 of the girls and
14 of the boys achieved Bronze certificates. How many girls did not achieve Bronze certificates?
| Boys |
Girls |
| 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 pupils who did not achieve Bronze certificates
= 175 - 58
= 117
2 u + 1 p = 58
1 p = 58 - 2 u --- (1)
3 u + 3 p = 117
3 p = 117 - 3 u --- (2)
Make p the same.
(1)
x33 p = 174 - 6 u --- (3)
(2) = (3)
117 - 3 u = 174 - 6 u
6 u - 3 u = 174 - 117
3 u = 57
1 u = 57 ÷ 3 = 19
Number of boys who achieved Bronze certificates
= 2 u
= 2 x 19
= 38
Number of girls who achieved Bronze certificates
= 58 - 38
= 20
Answer(s): 20
