Q&A - PSLE Math

[ozora]

tianzhu:

Hi


For Q1, a student should recognize that the amount of money stays the same after the transfer.

As for Q2, “Systematic Listing” is commonly used by students.
There are multiple answers to your question.
107 is one of them. I think there are three more answers, 119, 131 and 143.

Hope this helps.

Best wishes.

http://farm6.static.flickr.com/5180/5591186568_fff7a07f2b_z.jpg\">

http://farm6.static.flickr.com/5185/5590692977_b2c5469dc2_z.jpg\">

thanks i got the answer for question 2 is 107 but the given answer is 131. I was puzzled where did i go wrong.
I did the listing method.

[tianzhu]

shurley197323:

Thanks Tianzhu and cwc.

Hi shurley197323

Good Morning.

You're welcome.

Best wishes

[tianzhu]

ozora:

thanks i got the answer for question 2 is 107 but the given answer is 131. I was puzzled where did i go wrong.

I did the listing method.

Hi ozora

Good Morning.

You're welcome.

Best wishes

[tianzhu]

mvmir26:

Thank you very much for your help. Tianzhu.

Hi mvmir26

Good Morning.

You're welcome.

Best wishes

[tianzhu]

Hi jesschan


Good Morning.

I hope I’ve not kept you waiting for too long.

For your question, a P5 student should be able to use logical reasoning to breakdown the problem.

You are given the notes in denominations of $50, $5 and $2.

To add up to $1119, you need the value of $2 notes to end up in $4, $14,$24 … that is number ending with 4 because we are adding to multiples of $5 notes.

Using knowledge of number bonds, we have 1119 ----- 1100 + 15 + 4

Once a student is able to breakdown the question into this pattern, the rest of the calculations come into place. The next step is to allocate the right denominations of notes to add up to $1119.

An alternative solution is to use “Assumption Method”.

1119 ------ 1110 + 5 + 4

5 + 4 ----- use 1 number of $5 note and 2 number of $2 notes

Hence , the remaining 42 number of notes with a total value of $1110 consists of $50 and $5 notes.

Now, use “Assumption Method” to find the number of $50 notes and $5 notes.

Hope this helps.

Best wishes

http://farm6.static.flickr.com/5270/5594005936_5a18d57e90_z.jpg\">

[MathIzzzFun]

ozora:

tianzhu:

Hi


For Q1, a student should recognize that the amount of money stays the same after the transfer.

As for Q2, “Systematic Listing” is commonly used by students.
There are multiple answers to your question.
107 is one of them. I think there are three more answers, 119, 131 and 143.

Hope this helps.

Best wishes.

http://farm6.static.flickr.com/5180/5591186568_fff7a07f2b_z.jpg\">

http://farm6.static.flickr.com/5185/5590692977_b2c5469dc2_z.jpg\">

thanks i got the answer for question 2 is 107 but the given answer is 131. I was puzzled where did i go wrong.
I did the listing method.

Hi

The way the question is worded, there are more than one answer to Q2 - \"Joan bought some apples and put them into boxes.
if she put 4 apples into each box, there would be 3 apples left.
if she put 6 apples into each box, there would be 5 apples left.
if the number of apples was between 100 to 150, how many apples did Joan buy?.\"

If the last sentence of the question is \"If the number of apples was between 120 and 140, how many apples did Joan buy?\", then the answer is 131.

Solution:

When 4 apples are put into each box, 3 apples left => remainder of 3, which means that if one more apple is added, the total number will be divisible by 4

When 6 apples are put into each box, 5 apples left => remainder of 5, so if one more apple is added, the total number will be divisible by 6

From above, if one more apple is added, the total number is a number divisible by both 4 and 6, ie the answer is a multiple of both 4 & 6 minus 1.

LCM of 4 & 6 = 12

Between 100 and 150, the numbers divisible by both 4 & 6 are : 108, 120, 132, 144

So, possible answers are 107, 119, 131, 143.

check:
107 / 4 = 26 R3, 107 / 6 = 17 R5
119 / 4 = 29 R3, 119 / 6 = 19 R5
131 / 4 = 32 R3, 131 / 6 = 21 R5
143 / 4 = 35 R3, 143 / 6 = 23 R5

Hope this helps.

cheers.

[jesschan]

Got it! Thanks, Tianzhu.

[Hifive]

Hi


Need help with this question:

Mrs Tan bought a box of fruits. 30% of the fruits were pears and the rest oranges. She discovered that half of the pears were rotten and threw them away. She then bought some oranges and the number of oranges increased by 40%. After that, she found out that there were 52 more fruits in the box. How many fruits were there in the box at first?

Thanks in advance!

[jieheng]

Hifive:

Hi


Need help with this question:

Mrs Tan bought a box of fruits. 30% of the fruits were pears and the rest oranges. She discovered that half of the pears were rotten and threw them away. She then bought some oranges and the number of oranges increased by 40%. After that, she found out that there were 52 more fruits in the box. How many fruits were there in the box at first?

Thanks in advance!

P [30u]
O [-----70u----]
Total units of fruits -----> 30u + 70u = 100u

P [30u] - [15u]
O [-----70u----] + [28u]

P [15u]
O [-----98u----]
Total units of fruits -----> 15u + 98u = 113u

Increased in number of units of fruits -----> 113u - 100u = 13u

13u----->52
1u------->4

Number of fruits were there in the box at first = 100u = 100 * 4 = 400 (Ans)

[shurley197323]

Pls help.

After the tsunami, 250 blankets were given out to the people .Three children shared 1 blanket while 2 adults shared 1 blanket. If there were 650 people, how many of them were adults.
(No guess & check method, use assumption method please)