Q&A - P3 Math

[small]

tianzhu:

small:

Much appreciated if someone can help on this question, thanks.


P4 Question:
There were 54 cars and bicycles in a car park. Someone removed 1 wheel each from 4 bicycles. As a result, there were 180 wheels left. How many cars were there? (5 marks)
[/u]

Hi small

Use Make a Supposition, you‘ll get 38 cars and 16 bicycles.

Suppose there are 54 cars, you’ll have 216 wheels

216 - 184 ----32 (add 4 to 180 to account for 4 removed bicycle wheels)
32/2 ---- 16 bicycles
54 – 16 ---- 38 cars

Check
38 *4 --- 152
16*2 ---32
Total --- 184
184 - 4 ---180

Best wishes

Hi tianzhu, many thanks for your time. :celebrate:

I was trying to figure out how you get this 'add 4 to 180 to account for 4 removed bicycle wheels', Is it because of we supposed there are 16 bicycles? I will need some explanation to convince my son otherwise my son sure will ask me why ' 4' . :oops:
.

[tianzhu]

small:

I was trying to figure out how you get this 'add 4 to 180 to account for 4 removed bicycle wheels', Is it because of we supposed there are 16 bicycles? I will need some explanation to convince my son otherwise my son sure will ask me why ' 4' . :oops:
.

Hi small

Good Morning.

You're welcome.

The hint is from here, Someone removed 1 wheel each from 4 bicycles..

4 wheels are removed, so we have to add 4 to 180 to account for the removal when we are using the heuristics, Make a Supposition.

This question is tweaked as compared to the usual question which one is more familiar.

Consider this

There were 54 cars and bicycles in a car park. Mary noticed they had 180 wheels. How many cars were there?

This is another question with a tweak.

1) There are 85 plates of fried noodle for 80 people. Each adult eats 2 plates of fried noodle and every three children share 1 plate of fried noodle. How many adults and children are there?

Best wishes

[yeonee]

Thank you.

[Vanilla Cake]

tianzhu:

The hint is from here, Someone removed 1 wheel each from 4 bicycles..


4 wheels are removed, so we have to add 4 to 180 to account for the removal when we are using the heuristics, Make a Supposition.

This question is tweaked as compared to the usual question which one is more familiar.

Consider this

There were 54 cars and bicycles in a car park. Mary noticed they had 180 wheels. How many cars were there?

This is another question with a tweak.

1) There are 85 plates of fried noodle for 80 people. Each adult eats 2 plates of fried noodle and every three children share 1 plate of fried noodle. How many adults and children are there?

Another tweaked question that involves percentage (for P5 mainstream & above):

A farm has 40% more chickens than goats.Given that the chickens and goats have a total of 442 legs, find the number of chickens in the farm.

VC's mum

[Yu Xuan]

small:

Much appreciated if someone can help on this question, thanks.


P4 Question:
There were 54 cars and bicycles in a car park. Someone removed 1 wheel each from 4 bicycles. As a result, there were 180 wheels left. How many cars were there? (5 marks)
[/u]

May I 'busy-body' again...

By adding 4 wheels to the 180 wheels, we will have the logically 'actual' no. of wheels;

180 + 4 = 184
54 * 2 = 108
184 - 108 = 76
76 / 2 = 38 (Cars)

[peggy]

Can anyone help me with this P4 Qtn ?


Annie has an amount of cookies less than 60. If she packs in a bag of 5, there’ll be 2 left. But if she packs in a bag of 7, she’ll be short of 3. How many cookies does she has ?

Help !!!

[mrswongtuition]

peggy:

Can anyone help me with this P4 Qtn ?


Annie has an amount of cookies less than 60. If she packs in a bag of 5, there'll be 2 left. But if she packs in a bag of 7, she'll be short of 3. How many cookies does she has ?

Help !!!

Multiples of 5 + 2 left:
7, 12, 17, 22, 27, 32, 37, 42, 47, 52, 57

Multiples of 7 - 3 short:
4, 11, 18, 25, 32, 39, 46, 53, 60


Common: 32

She has 32 cookies.

[yeonee]

peggy:

Can anyone help me with this P4 Qtn ?


Annie has an amount of cookies less than 60. If she packs in a bag of 5, there'll be 2 left. But if she packs in a bag of 7, she'll be short of 3. How many cookies does she has ?

Help !!!

Hi, I learn from somewhere you can apply the following method:-

Multiple of 5
5,10,15,20,25,30,35,40,45,50,55
(+2)
7,12,17,22,27,32,37,42,47,52,57

Multiple of 7
7,14,21,28,35,42,49,56,63
(-3)
4,11,18,25,32,39,46,53,60

The answer is 32 cookies

[peggy]

yeonee,


Thank you so much for sharing !!
And the explanation is very clear.

[yeonee]

peggy:

yeonee,


Thank you so much for sharing !!
And the explanation is very clear.

You are welcome.