110 students went for a dancing competition and 34 of them achieved Silver certificates.
25 of the boys and
15 of the girls achieved Silver certificates. How many boys did not achieve Silver certificates?
Girls |
Boys |
5 u |
5 p |
Achieved Silver |
Did not achieve Silver |
Achieved Silver |
Did not achieve Silver |
2 u |
3 u |
1 p |
4 p |
Number of students who did not achieve Silver certificates
= 110 - 34
= 76
2 u + 1 p = 34
1 p = 34 - 2 u --- (1)
3 u + 4 p = 76
4 p = 76 - 3 u --- (2)
Make p the same.
(1)
x44 p = 136 - 8 u --- (3)
(2) = (3)
76 - 3 u = 136 - 8 u
8 u - 3 u = 136 - 76
5 u = 60
1 u = 60 ÷ 5 = 12
Number of girls who achieved Silver certificates
= 2 u
= 2 x 12
= 24
Number of boys who achieved Silver certificates
= 34 - 24
= 10
Answer(s): 10