PSLE The number of girls and boys taking part in a contest are in the ratio 1 : 8. These pupils are put into two teams. 40% 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 boys in Team F is more than 70. What is the smallest possible total number of pupils taking part in the contest?
Girls |
Boys |
10 u |
80 u |
Team F |
Team G |
Team F |
Team G |
4 u |
6 u |
8 u |
72 u |
(a)
Girls : Boys
1 : 8
10 : 80
Number of girls in Team F
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of girls in Team G
= 10 u - 4 u
= 6 u
Number of boys in Team F
= 10% x 80 u
=
10100 x 80 u
= 8 u
Number of boys in Team G
= 80 u - 8 u
= 72 u
Team F : Team G
6 + 72 : 4 + 8
78 : 12
(÷6)13 : 2
(b)
Number of boys in Team F = 8 u
Since the number of boys in Team F is 8 u, it must be multiple of 8.
Number of sets of 8
= 70 ÷ 8
= 8 r 6
Since the number of boys in Team F is more than 70, the number of sets must be 1 more than 8.
1 u = 8 + 1 = 9
Smallest possible number of pupils
= 10 u + 80 u
= 90 u
= 90 x 9
= 810
Answer(s): (a) 13 : 2; (b) 810