This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Wednesday, February 10, 2010

Ai Tong Sch 2009 P6 CA1 Math Paper 2 Q18

Ai Tong School organized a 2-day camp. On the first day, the number of boys was 600 more than the girls. On the second day, the number of boys decreased by 10% but the number of girls increased by 10%. If there were 2540 children on the second day, how many children were there on the first day?

Solution


2nd Day
Boys --> 0.9 unit + 540
Girls --> 1.1 unit
Total --> 2540

0.9 unit + 540 + 1.1 unit --> 2540
2 units + 540 --> 2540
2 units --> 2540 - 540 = 2000
1 unit --> 2000 divided by 2 = 1000

1st Day
2 units + 600
(2 x 1000) + 600
= 2000 + 600
= 2600

Answer: 2600 children

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