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.

## Tuesday, February 15, 2011

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I am a Primary 6 Student and have been reading your blog since P5. I would like to ask for your help in the 2 questions from Pei Hwa Presbyterian CA1 Math paper:

Paper2
Q18:
7 apples cost \$4
9 oranges cost \$11
James bought a total of 1000 apples and oranges for \$999.
How many apples and how many oranges did he buy?

Q5:
297 digits are used to print the page numbers of a story book.
What is the number on the last page number of the story book?

Thank you so much and happy new year.

Anonymous said...

1 to 9 have 9 digits
10 to 99 have 180 digits
100 to 135 have 108 digits

9+180+108 gives 297 digits.

Hence the number on the last page number is 135.

Anonymous said...

Let A = total numbers of Apples
and B = total number of Oranges.
( I used B instead of O )

(A/7)4 + ( B/9 ) 11 = 999
4A/7 + 11B/9 = 999
( 36A + 77B )/63 = 999
36A + 77B = 62937 ------ (1)

B + A = 1000
A = 1000 - B ------------ (2)

Sub (2) into (1)

36( 1000 - B ) + 77B = 62937
36000 – 36B + 77B = 62937
41B = 62937 – 36000 = 26937
B = 26937/41 = 657

A = 1000 – 657 = 343

So, James bought 343 apples and 657 oranges.