## P6 Percentage ( Minutes To Score) 3 years 10 months ago #1

 Tham Lin Ching Offline Karma: 0 There were 40% more boys than girls who took part in a drawing competition. After 55 boys and 55 girls joined, there were 30% more boys than girls in the competion. How many boys and girls were there at first? The administrator has disabled public write access.

## P6 Percentage ( Minutes To Score) 2 years 9 months ago #2

 Rex Fernando Offline Karma: 1 This is bit tricky and must use algebra to solve. Let us assume B boys and G girls at first. so, B = 1.4G (40% more) Then: (B + 55) = 1.3(G + 55) B + 55 = 1.3G + 71.5 1.4G + 55 = 1.3G + 71.5 (replacing B with 1.4G) 1.4G - 1.3G = 71.5 - 55 = 16.5 Therefore, 0.1G = 16.5 and G = 165. B = 1.4 X 165 = 231 Girls at first = 165 Boys at first = 231 The administrator has disabled public write access.

## P6 Percentage ( Minutes To Score) 2 years 9 months ago #3

 Fibonacci Offline Karma: 13 Since 40% more boys than girls, Ratio of B : G = 7 : 5 When 55 boys and 55 girls joined, difference remained unchanged Ratio (end) B : G = 13 : 10 Make the difference between the two sets of ratios the same: at first end B : G : Difference B : G : Difference 7 : 5 : 2 13 : 10 : 3 21 : 15 : 6 26 : 20 : 6 Can you see that the change in boys is 5 units and the change in girls is also 5 units? Hence, 5units = 55 1unit = 11 Total (at first) = 21units + 15units = 36units 36units = 396 The administrator has disabled public write access. The following user(s) said Thank You: Mei Yong Loh
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