125 pupils went for a dancing competition and 63 of them achieved Gold certificates.
35 of the girls and
13 of the boys achieved Gold certificates. How many girls did not achieve Gold certificates?
| Boys |
Girls |
| 5 u |
3 p |
Achieved
Gold |
Did not achieve
Gold |
Achieved
Gold |
Did not achieve
Gold |
| 3 u |
2 u |
1 p |
2 p |
Number of pupils who did not achieve Gold certificates
= 125 - 63
= 62
3 u + 1 p = 63
1 p = 63 - 3 u --- (1)
2 u + 2 p = 62
2 p = 62 - 2 u --- (2)
Make p the same.
(1)
x22 p = 126 - 6 u --- (3)
(2) = (3)
62 - 2 u = 126 - 6 u
6 u - 2 u = 126 - 62
4 u = 64
1 u = 64 ÷ 4 = 16
Number of boys who did not achieve Gold certificates
= 2 u
= 2 x 16
= 32
Number of girls who did not achieve Gold certificates
= 62 - 32
= 30
Answer(s): 30
