152 pupils went for a singing competition and 73 of them achieved Bronze certificates.
35 of the boys and
14 of the girls achieved Bronze certificates. How many boys did not achieve Bronze certificates?
| Girls |
Boys |
| 5 u |
4 p |
Achieved
Bronze |
Did not achieve
Bronze |
Achieved
Bronze |
Did not achieve
Bronze |
| 3 u |
2 u |
1 p |
3 p |
Number of pupils who did not achieve Bronze certificates
= 152 - 73
= 79
3 u + 1 p = 73
1 p = 73 - 3 u --- (1)
2 u + 3 p = 79
3 p = 79 - 2 u --- (2)
Make p the same.
(1)
x33 p = 219 - 9 u --- (3)
(2) = (3)
79 - 2 u = 219 - 9 u
9 u - 2 u = 219 - 79
7 u = 140
1 u = 140 ÷ 7 = 20
Number of girls who did not achieve Bronze certificates
= 2 u
= 2 x 20
= 40
Number of boys who did not achieve Bronze certificates
= 79 - 40
= 39
Answer(s): 39
