Iran and Thailand took part in Youth Games. From Iran, the ratio of the number of male supporters to the number of female supporters was 4 : 9. From Thailand, the ratio of the number of male supporters to the number of female supporters was 3 : 4. The total number of supporters from Iran was ¹³₂₁ the total number of supporters from Thailand.

1. What was the ratio of the number of male supporters from Iran to the total number of male supporters from both countries? Express the answer in the simplest form.
2. After 72 male supporters from both countries left the games, the percentage of all the female supporters became 84%. How many more female supporters from Thailand than Iran were there at first?

Iran		Thailand
13 u		21 u
Male supporters	Female supporters	Male supporters	Female supporters
4	9	3x3	4x3
4 u	9 u	9 u	12 u

(a)
Number of male supporters from Thailand
= ³₇ x 21 u
= 9 u

Number of female supporters from Iran
= ⁴₇ x 21 u
= 12 u

Total number of male supporters
= 4 u + 9 u
= 13 u

Male supporters from Iran : Total male supporters
4 : 13

(b)

	Male supporters	Female supporters
Before	13x4 = 52%	21x4 = 84%
Change	- 72
After	16%	84%

Number of male supporters in the end in percent
= 100% - 84%
= 16%

Total number of female supporters at first
= 9 u + 12 u
= 21 u

After 72 male supporters from both countries left the games, the percentage of all the female supporters became 84%.

Since only male supporters left the games, the number of female supporters remains unchanged. Make the number of female supporters the same.

21 u = 84%

1 u = 84% ÷ 21 = 4%

Number of male supporters at first in percent
= 13 x 4%
= 52%

Number of male supporters from both countries who left
= 52% - 16%
= 36%

36% = 72 

1% = 72 ÷ 36 = 2

Number of more female supporters from Thailand than Iran at first
= 12 u - 9 u
= 3 u
= 3 x 4%
= 12%
= 12 x 2
= 24 

Answer(s): (a) 4 : 13; (b) 24