135 students went for a dancing competition and 42 of them achieved Gold certificates.
25 of the boys and
15 of the girls achieved Gold certificates. How many boys did not achieve Gold certificates?
| Girls |
Boys |
| 5 u |
5 p |
Achieved
Gold |
Did not achieve
Gold |
Achieved
Gold |
Did not achieve
Gold |
| 2 u |
3 u |
1 p |
4 p |
Number of students who did not achieve Gold certificates
= 135 - 42
= 93
2 u + 1 p = 42
1 p = 42 - 2 u --- (1)
3 u + 4 p = 93
4 p = 93 - 3 u --- (2)
Make p the same.
(1)
x44 p = 168 - 8 u --- (3)
(2) = (3)
93 - 3 u = 168 - 8 u
8 u - 3 u = 168 - 93
5 u = 75
1 u = 75 ÷ 5 = 15
Number of girls who achieved Gold certificates
= 2 u
= 2 x 15
= 30
Number of boys who achieved Gold certificates
= 42 - 30
= 12
Answer(s): 12
