129 pupils went for a physical fitness test and 62 of them achieved Bronze certificates.
35 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 |
| 3 u |
2 u |
1 p |
3 p |
Number of pupils who did not achieve Bronze certificates
= 129 - 62
= 67
3 u + 1 p = 62
1 p = 62 - 3 u --- (1)
2 u + 3 p = 67
3 p = 67 - 2 u --- (2)
Make p the same.
(1)
x33 p = 186 - 9 u --- (3)
(2) = (3)
67 - 2 u = 186 - 9 u
9 u - 2 u = 186 - 67
7 u = 119
1 u = 119 ÷ 7 = 17
Number of girls who achieved Bronze certificates
= 3 u
= 3 x 17
= 51
Number of boys who achieved Bronze certificates
= 62 - 51
= 11
Answer(s): 11
