Whole Number P6 2010 SA2 CHIJ P2 Q11

There were some magnets in a box for sale. Mrs Frank bought ½ of the magnets in the box and was given 5 magnets free of charge. Next, Mrs Samson bought ½ of the remaining magnets and was given 3 magnets free of charge.Later, Mrs Parker bought ½ of the remaining magnets and was given 2 magnets free of charge.If there were a dozen magnets left in the box, how many magnets were there at first? [4 marks][Answer given: 134]


12 + 2 = 14

14 x 2 = 28


28 + 3 = 31

31 x 2 = 62


62 + 5 = 67

67 x 2 = 134 magnets

Whole Number P6 2010 CHIJ P2 Q18

Hiroshi collects gamecards. Every day, he gets 10 additional new gamecards. On every third day, he gives three cards to his friend, Miki, If Hiroshi starts with eight cards on the first day, on which day will he have exactly 180 cards?[5 marks][20th day]


Day 1 --> 8

Day 2 --> 8 + 10 = 18

Day 3 --> 18 + 10 = 28

Day 4 --> 28 + 10 - 3 = 35

35 - 8 = 27

180 - 8 = 172

172/27 = 6 r 10

6 x 3 = 18

1 + 18 + 1 = 20th day

It was the 20th day.