PSLE The number of boys and girls taking part in a test are in the ratio 7 : 3. These students are put into two teams. 10% of the boys and 50% of the girls are in Team A. The rest of the students are in Team B.
- What is the ratio of the number of students in Team B to Team A? Give your answer in the simplest form.
- The number of girls in Team A is more than 50. What is the smallest possible total number of students taking part in the test?
Boys |
Girls |
70 u |
30 u |
Team A |
Team B |
Team A |
Team B |
7 u |
63 u |
15 u |
15 u |
(a)
Boys : Girls
7 : 3
70 : 30
Number of boys in Team A
= 10% x 70 u
=
10100 x 70 u
= 7 u
Number of boys in Team B
= 70 u - 7 u
= 63 u
Number of girls in Team A
= 50% x 30 u
=
50100 x 30 u
= 15 u
Number of girls in Team B
= 30 u - 15 u
= 15 u
Team A : Team B
63 + 15 : 7 + 15
78 : 22
(÷2)39 : 11
(b)
Number of girls in Team A = 15 u
Since the number of girls in Team A is 15 u, it must be multiple of 15.
Number of sets of 15
= 50 ÷ 15
= 3 r 5
Since the number of girls in Team A is more than 50, the number of sets must be 1 more than 3.
1 u = 3 + 1 = 4
Smallest possible number of students
= 70 u + 30 u
= 100 u
= 100 x 4
= 400
Answer(s): (a) 39 : 11; (b) 400