Q&A - PSLE Math

[tianzhu]

Mum1113:

Not sure if this been shared before. Just like to share answer from ds, he is using assumption method.

Hi

Thank you for sharing.

Yes, Assumption method may be used.

Best wishes

[tianzhu]

trytry:

A courier company charged $25 for every large parcel and $15 for every

small parcel delivered safely. However, a penalty of $50 was charged for
every damaged parcel regardless of size.
This month, the company delivered 120 parcels of which 1/4 of them were
small parcels. It collected a total of $2000 after paying a penalty for
an equal numbers of large and small parcels.
How many large pacels were delivered safely?
(Nanyang 2010 SA1 P2 Q12)
The answer provided was 83. But mine is 85. Which is correct?

Hi

Please refer to Tang's answer.

Best wishes

[Tang]

tianzhu:

trytry:

A courier company charged $25 for every large parcel and $15 for every

small parcel delivered safely. However, a penalty of $50 was charged for
every damaged parcel regardless of size.
This month, the company delivered 120 parcels of which 1/4 of them were
small parcels. It collected a total of $2000 after paying a penalty for
an equal numbers of large and small parcels.
How many large pacels were delivered safely?
(Nanyang 2010 SA1 P2 Q12)
The answer provided was 83. But mine is 85. Which is correct?

Hi

83 is correct.

Best wishes

Hi,

85 is the correct answer.


85 x 25 = 2125

25 x 15 = 375

2125 + 375 = 2500

5 + 5 = 10

10 x 50 = 500

2500 - 500 = $2000 (amount collected).



Solution as follows:

120/4 = 30 small parcels

120 - 30 = 90 large parcels

Assume all dilivered safely, amount collected

90 x 25 + 30 x 15 = $2700



2700 - 2000 = $700 (too much)


Removing 1 large and 1 small parcels,

amount collected less by 25 + 15 = 40

penalty paid 50 + 50 = 100


Total amount reduced by 40 + 100 = $140


700/140 = 5, i.e. 5 large and 5 small parcels damaged.

90 - 5 = 85 large parcels were delivered safely.

[tianzhu]

Hi trytry


Tang is correct.

The answer is 85.

Best wishes

[rossypolly]

hi there! Pls help me with this qn


Sam bought some vanilla cookies and gave 1/2 of them to Mike.
Mike bought some chocholate bars and gave 1/2 of them to Sam.
Sam ate 8 chocolate bars and Mike ate 16 vanilla cookies.
The ratio of Sam’s vanilla cookies to chocolate bars became 8:1 and the ratio of Mike’s vanilla cookies to chocolate bars became 3:1.

How many vanilla cookies did Sam buy?

(Really appreciate your help)

[small]

Please help and TIA..


Question: For every tree that Imran plants, he is paid $4. A bonus of 20 is given to him for every 25 trees he plants within the same day. On the average, how trees must Imran plant a day if he wishes to earn a total of $760 over a period of 5 days?

.

[tianzhu]

small:

Please help and TIA..


Question: For every tree that Imran plants, he is paid $4. A bonus of 20 is given to him for every 25 trees he plants within the same day. On the average, how trees must Imran plant a day if he wishes to earn a total of $760 over a period of 5 days?

.

Hi small

Good Morning

760/5 --- 152

For 25 trees, he earned (100+20) ----- 120

152 ----- 120+32

32/4 ----- 8

Number of trees ------ 25+8 ------33

Best wishes

[tianzhu]

rossypolly:

hi there! Pls help me with this qn


Sam bought some vanilla cookies and gave 1/2 of them to Mike.
Mike bought some chocholate bars and gave 1/2 of them to Sam.
Sam ate 8 chocolate bars and Mike ate 16 vanilla cookies.
The ratio of Sam's vanilla cookies to chocolate bars became 8:1 and the ratio of Mike's vanilla cookies to chocolate bars became 3:1.

How many vanilla cookies did Sam buy?

(Really appreciate your help)

Hi rossypolly

Good Morning

This question is pretty similar to Q18 of PSLE Maths 2009.It has been discussed previously in this forum.

Due to time constraints, I’d not draw the MD this time, hope the following pointers would help you to draw the MD yourself.

After Sam had eaten 8 chocolates
Vanilla ----- 8 units
Chocolate -----1 unit

After Mike had eaten 16 vanilla cookies
Vanilla ----- 3 parts
Chocolate ----- 1 part
1 part ------ 1 unit+8

Now, compare, the MD for vanilla cookies

3 units + 24 + 16 -------8 units
5 units ----- 40
1 unit ------8
8 units ----- 64

Sam had 128 vanilla cookies.

If you need the MD, please let me know. I’ll draw it at a later time if there is no MD solution from others.

Best wishes

[small]

tianzhu:

small:

Please help and TIA..


Question: For every tree that Imran plants, he is paid $4. A bonus of 20 is given to him for every 25 trees he plants within the same day. On the average, how trees must Imran plant a day if he wishes to earn a total of $760 over a period of 5 days?

.

Hi small

Good Morning

760/5 --- 152

For 25 trees, he earned (100+20) ----- 120

152 ----- 120+32

32/4 ----- 8

Number of trees ------ 25+8 ------33

Best wishes

Good morning Tianzhu,

Thanks very much... :celebrate:

No wonder I got the wrong answer. Wrong step always give me the wrong answer.
I did not divide the total money with 5 days first, instead I divided $750 with $120.


.

[tianzhu]

small:

Good morning Tianzhu,

Thanks very much... :celebrate:

No wonder I got the wrong answer. Wrong step always give me the wrong answer.
I did not divide the total money with 5 days first, instead I divided $750 with $120.

Hi

You're welcome.

Best wishes