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.

Thursday, July 10, 2008

S’pore Hokkien Huay Kuan 2007 PSLE Math Prelim Q47

Ahmad formed the following patterns using toothpicks.





a) How many toothpicks would Ahmad need to form Pattern 4?
b) If the last pattern formed by Ahmad had 165 toothpicks, what was the pattern number?


Solution


a)
Pattern 1 –---- 3
Pattern 2 ----- (3 + 6) = 9
Pattern 3 ----- (6 + 9) = 18
Pattern 4 ----- (18 + 12) = 30

Answer: 30

b)
Pattern 5 ----- (30 + 15) = 45
Pattern 6 ----- (45 + 18) = 63
Pattern 7 ----- (63 + 21) = 84
Pattern 8 ----- (84 + 24) = 108
Pattern 9 ----- (108 + 27) = 135
Pattern 10 ----- (135 + 30) = 165

Answer: Pattern 10

Note – “The Singapore Hokkien Huay Kuan 5-School Combined Prelim Maths” is the common Maths Prelim Exam for Tao Nan, Ai Tong, Chongfu, Nan Chiau and Kong Hwa schools.

8 comments:

keentolearn said...

Dear Mr Song
If you have done this question in your database, could you please help to confirm if the answers as given in the worksheet a) 7:1:8 and b) 168 are correct. If not what are the correct answers? Just the answers not detailed solution, if you could help.

(Ai Tong School P6 SA1 Q43 - 2007)
Packets of assorted candies were sold in 2 different sizes - standard and large. The large packet contained twice as many candies as the standard packet. In the standard packet, the ratio of the number of coconut candies to the number of strawberry candies were 4:5. In the large packet, the ratio of the number of coconut candies to the number of strawberry candies to the number of toffee candies was 1: 2: 3.

A family bought 1 standard and 1 large packet.

(a) What was the ratio of the number of coconut candies to the number of strawberry candies to the number of toffee candies?

(b) The family ate 21 candies. As a result, the ratio of the number of coconut candies to the number of strawberry candies to the number of toffee candies became 2: 3: 3. How many candies were left?

Excel Eduservice said...

Apologies, I don't have that Q in the database (for now).

keentolearn said...

Dear Mr Song
Thank You

Anonymous said...

i worked out to be
a) 7:11:9
b) 168

keentolearn said...

To anonymous

Thank You

Observer said...

Should part (b) be

The family ate 21 'coconut coconut and strawberry candies' (instead of 'candies')?

Observer said...

You can get answer of 168 for part b only if you assume that 21 coconut and strawberry candies were eaten, otherwise you cannot proceed.

Observer said...

Ok no issue. Just have to try to make sure the total difference is a factor of 21.