PSLE The number of boys and girls taking part in a contest are in the ratio 5 : 4. These pupils are put into two teams. 20% of the boys and 30% of the girls are in Team V. The rest of the pupils are in Team W.
- What is the ratio of the number of pupils in Team W to Team V? Give your answer in the simplest form.
- The number of girls in Team V is more than 90. What is the smallest possible total number of pupils taking part in the contest?
Boys |
Girls |
50 u |
40 u |
Team V |
Team W |
Team V |
Team W |
10 u |
40 u |
12 u |
28 u |
(a)
Boys : Girls
5 : 4
50 : 40
Number of boys in Team V
= 20% x 50 u
=
20100 x 50 u
= 10 u
Number of boys in Team W
= 50 u - 10 u
= 40 u
Number of girls in Team V
= 30% x 40 u
=
30100 x 40 u
= 12 u
Number of girls in Team W
= 40 u - 12 u
= 28 u
Team V : Team W
40 + 28 : 10 + 12
68 : 22
(÷2)34 : 11
(b)
Number of girls in Team V = 12 u
Since the number of girls in Team V is 12 u, it must be multiple of 12.
Number of sets of 12
= 90 ÷ 12
= 7 r 6
Since the number of girls in Team V is more than 90, the number of sets must be 1 more than 7.
1 u = 7 + 1 = 8
Smallest possible number of pupils
= 50 u + 40 u
= 90 u
= 90 x 8
= 720
Answer(s): (a) 34 : 11; (b) 720