130 pupils went for a spelling test and 70 of them achieved Bronze certificates.
35 of the boys and
13 of the girls achieved Bronze certificates. How many boys did not achieve Bronze certificates?
Girls |
Boys |
5 u |
3 p |
Achieved Bronze |
Did not achieve Bronze |
Achieved Bronze |
Did not achieve Bronze |
3 u |
2 u |
1 p |
2 p |
Number of pupils who did not achieve Bronze certificates
= 130 - 70
= 60
3 u + 1 p = 70
1 p = 70 - 3 u --- (1)
2 u + 2 p = 60
2 p = 60 - 2 u --- (2)
Make p the same.
(1)
x22 p = 140 - 6 u --- (3)
(2) = (3)
60 - 2 u = 140 - 6 u
6 u - 2 u = 140 - 60
4 u = 80
1 u = 80 ÷ 4 = 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
= 60 - 40
= 20
Answer(s): 20