139 pupils went for a spelling test and 68 of them achieved Gold certificates.
35 of the girls and
14 of the boys achieved Gold certificates. How many girls did not achieve Gold certificates?
| Boys |
Girls |
| 5 u |
4 p |
Achieved
Gold |
Did not achieve
Gold |
Achieved
Gold |
Did not achieve
Gold |
| 3 u |
2 u |
1 p |
3 p |
Number of pupils who did not achieve Gold certificates
= 139 - 68
= 71
3 u + 1 p = 68
1 p = 68 - 3 u --- (1)
2 u + 3 p = 71
3 p = 71 - 2 u --- (2)
Make p the same.
(1)
x33 p = 204 - 9 u --- (3)
(2) = (3)
71 - 2 u = 204 - 9 u
9 u - 2 u = 204 - 71
7 u = 133
1 u = 133 ÷ 7 = 19
Number of boys who did not achieve Gold certificates
= 2 u
= 2 x 19
= 38
Number of girls who did not achieve Gold certificates
= 71 - 38
= 33
Answer(s): 33
