175 pupils went for a physical fitness test and 69 of them achieved Gold certificates.
35 of the girls and
15 of the boys achieved Gold certificates. How many girls did not achieve Gold certificates?
| Boys |
Girls |
| 5 u |
5 p |
Achieved
Gold |
Did not achieve
Gold |
Achieved
Gold |
Did not achieve
Gold |
| 3 u |
2 u |
1 p |
4 p |
Number of pupils who did not achieve Gold certificates
= 175 - 69
= 106
3 u + 1 p = 69
1 p = 69 - 3 u --- (1)
2 u + 4 p = 106
4 p = 106 - 2 u --- (2)
Make p the same.
(1)
x44 p = 276 - 12 u --- (3)
(2) = (3)
106 - 2 u = 276 - 12 u
12 u - 2 u = 276 - 106
10 u = 170
1 u = 170 ÷ 10 = 17
Number of boys who did not achieve Gold certificates
= 2 u
= 2 x 17
= 34
Number of girls who did not achieve Gold certificates
= 106 - 34
= 72
Answer(s): 72
