PSLE The number of girls and boys taking part in a test are in the ratio 1 : 4. These students are put into two teams. 70% of the girls and 20% of the boys are in Team D. The rest of the students are in Team E.
- What is the ratio of the number of students in Team E to Team D? Give your answer in the simplest form.
- The number of boys in Team D is more than 60. What is the smallest possible total number of students taking part in the test?
Girls |
Boys |
10 u |
40 u |
Team D |
Team E |
Team D |
Team E |
7 u |
3 u |
8 u |
32 u |
(a)
Girls : Boys
1 : 4
10 : 40
Number of girls in Team D
= 70% x 10 u
=
70100 x 10 u
= 7 u
Number of girls in Team E
= 10 u - 7 u
= 3 u
Number of boys in Team D
= 20% x 40 u
=
20100 x 40 u
= 8 u
Number of boys in Team E
= 40 u - 8 u
= 32 u
Team D : Team E
3 + 32 : 7 + 8
35 : 15
(÷5)7 : 3
(b)
Number of boys in Team D = 8 u
Since the number of boys in Team D is 8 u, it must be multiple of 8.
Number of sets of 8
= 60 ÷ 8
= 7 r 4
Since the number of boys in Team D is more than 60, the number of sets must be 1 more than 7.
1 u = 7 + 1 = 8
Smallest possible number of students
= 10 u + 40 u
= 50 u
= 50 x 8
= 400
Answer(s): (a) 7 : 3; (b) 400