Norway and Korea took part in Youth Games. From Norway, the ratio of the number of male supporters to the number of female supporters was 1 : 10. From Korea, the ratio of the number of male supporters to the number of female supporters was 1 : 5. The total number of supporters from Norway was ¹¹₁₈ the total number of supporters from Korea.

1. What was the ratio of the number of male supporters from Norway to the total number of male supporters from both countries? Express the answer in the simplest form.
2. After another 156 male supporters from both countries joined the games, the percentage of all the female supporters became 75%. How many less female supporters from Norway than Korea were there at first?

Norway		Korea
11 u		18 u
Male supporters	Female supporters	Male supporters	Female supporters
1	10	1x3	5x3
1 u	10 u	3 u	15 u

(a)
Number of male supporters from Korea
= ¹₆ x 18 u
= 3 u

Number of female supporters from Norway
= ⁵₆ x 18 u
= 15 u

Total number of male supporters
= 1 u + 3 u
= 4 u

Male supporters from Norway : Total male supporters
1 : 4

(b)

	Male supporters	Female supporters
Before	4x3 = 12%	25x3 = 75%
Change	+ 156
After	25%	75%

Number of male supporters in the end in percent
= 100% - 75%
= 25%

Total number of female supporters at first
= 10 u + 15 u
= 25 u

After another 156 male supporters from both countries joined the games, the percentage of all the female supporters became 75%.

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

25 u = 75%

1 u = 75% ÷ 25 = 3%

Number of male supporters at first in percent
= 4 x 3%
= 12%

Number of male supporters from both countries who joined the games
= 25% - 12%
= 13%

13% = 156 

1% = 156 ÷ 13 = 12

Number of less female supporters from Norway than Korea at first
= 15 u - 10 u
= 5 u
= 5 x 3%
= 15%
= 15 x 12
= 180 

Answer(s): (a) 1 : 4; (b) 180