PSLE The number of girls and boys taking part in a test are in the ratio 3 : 7. These pupils are put into two teams. 70% of the girls and 10% of the boys are in Team F. The rest of the pupils are in Team G.
- What is the ratio of the number of pupils in Team G to Team F? Give your answer in the simplest form.
- The number of girls in Team G is fewer than 80. What is the largest possible total number of pupils taking part in the test?
Girls |
Boys |
30 u |
70 u |
Team F |
Team G |
Team F |
Team G |
21 u |
9 u |
7 u |
63 u |
(a)
Girls : Boys
3 : 7
30 : 70
Number of girls in Team F
= 70% x 30 u
=
70100 x 30 u
= 21 u
Number of girls in Team G
= 30 u - 21 u
= 9 u
Number of boys in Team F
= 10% x 70 u
=
10100 x 70 u
= 7 u
Number of boys in Team G
= 70 u - 7 u
= 63 u
Team G : Team F
9 + 63 : 21 + 7
72 : 28
(÷4)18 : 7
(b)
Number of girls in Team G = 9 u
Since the number of girls in Team G is 9 u, it must be multiple of 9.
Number of sets of 9
= 80 ÷ 9
= 8 r 8
Since the number of girls in Team G is less than 80, the number of sets must be 8.
1 u = 8
Largest possible number of pupils
= 30 u + 70 u
= 100 u
= 100 x 8
= 800
Answer(s): (a) 18 : 7; (b) 800