Q&A - PSLE Math

[ABCDE]

tianzhu:

Hi


You may wish to try these two questions.

1) Tommy had six more 50-cent coins than 20-cent coins. After he used eight 50-cent coins, the value of the 50-cent coins is $7.40 more than the value of 20-cent coins. How many coins did he have at first?

2) Some plates and cups were packed into blue and red boxes. There were 12 more blue boxes than red boxes. Each blue box contained 120 plates and each red box contained 150 cups. Given that there were 120 fewer plates than cups in total, how many plates were there?

Best wishes

Hi Tianzhu,
Please confirm wht the answers are as follows:

2) 7680 plates
1) 62 coins

[kancheongmum]

Hi VC’s mum


Your DD2 will sure ace PSLE. My DS can’t solve Q1 and he is taking PSLE in 2 weeks. He always think too much for a simple question. On the 2nd attempt he uses fraction to solve which is also the solution provided by the school, the setter of question. Just for info:

sb - small box
bb - big box

14sb —3/8
1 sb — 3/112

15 bb — 5/8 —70/112
1bb — 14/336

1sb — 3/112 — 9/336

14/336 - 9/336 — 5/336 —5 beads
1/336 — 1 bead
1 small box — 9 x 1 = 9 beads

It is ok for me as long as the working is logical and he gets the answer. Cannot do much now as PSLE is just 2 wks away, putting too much things in his head will get him confuse. I wish he can solve this way:

3u — 14 small box
5u — 15 big box
1u — 3 big box
3u — 9 big box
1 big box = 1 small box + 5 beads
9 big box = 14 small box
9 small box + 45 beads = 14 small box
5 small box ---- 45 beads
1 small box = 45/5 = 9 beads

[tianzhu]

ABCDE:

Hi Tianzhu,
Please confirm wht the answers are as follows:

2) 7680 plates
1) 62 coins

Hi ABCDE

I am sorry; I don’t have the answers at this moment.

For the benefits of PSLE students, would you like to share your solutions?

Best wishes

[Vanilla Cake]

ABCDE:

Hi VC mum,


Can u post Qt :11 from NY 2010 prelim for me.
Thanks

Refer to http://psle2010a.blogspot.com/2010/09/volume-p6-2010-sa2-nanyang-p2-q-11.html.

[Vanilla Cake]

kancheongmum:

Hi VC's mum


Your DD2 will sure ace PSLE. My DS can't solve Q1 and he is taking PSLE in 2 weeks. He always think too much for a simple question. On the 2nd attempt he uses fraction to solve which is also the solution provided by the school, the setter of question. Just for info:

sb - small box
bb - big box

14sb ---3/8
1 sb --- 3/112

15 bb --- 5/8 ---70/112
1bb --- 14/336

1sb --- 3/112 --- 9/336

14/336 - 9/336 --- 5/336 ---5 beads
1/336 --- 1 bead
1 small box --- 9 x 1 = 9 beads

It is ok for me as long as the working is logical and he gets the answer. Cannot do much now as PSLE is just 2 wks away, putting too much things in his head will get him confuse. I wish he can solve this way:

3u --- 14 small box
5u --- 15 big box
1u --- 3 big box
3u --- 9 big box
1 big box = 1 small box + 5 beads
9 big box = 14 small box
9 small box + 45 beads = 14 small box
5 small box ---- 45 beads
1 small box = 45/5 = 9 beads

Hi kancheongmum,

Could you pls advise the question number for the 2 questions from ACS 2010 P6 Prelim Paper 2?
Here's Observer's solutions for http://psle2010a.blogspot.com/2010/09/fraction-p6-20010-sa2-acs-p2-q.html and http://psle2010a.blogspot.com/2010/09/volume-p6-2010-sa2-acs-p2-q.html.

VC's mum

[kancheongmum]

Hi VC mum

beads Q13, tank Q16

[ABCDE]

Vanilla Cake:

ABCDE:

Hi VC mum,


Can u post Qt :11 from NY 2010 prelim for me.
Thanks

Refer to http://psle2010a.blogspot.com/2010/09/volume-p6-2010-sa2-nanyang-p2-q-11.html.

HI VC mum,

Thank u very much.I searched in tht website too..Couldn't find. HOw to search topic wise in obs website. Any tips??

[ABCDE]

tianzhu:

ABCDE:

Hi Tianzhu,
Please confirm wht the answers are as follows:

2) 7680 plates
1) 62 coins

Hi ABCDE

I am sorry; I don’t have the answers at this moment.

For the benefits of PSLE students, would you like to share your solutions?

Best wishes

Hi uncle,
I'm a student taking PSLE this year. Pl.bear with me for my typo skills. I'm very poor in this..Here is my wrking.Pls. correct me if I am wrong:
Qt: 1)
50 cent ------ X + 6
20 cent ------ X
After he used eight 50-cent coins,
50 cent ------ X + 6 - 8 = X -2
20 cent ------- X

Value of
50 Cent ----(x-2) x 0.5 = 0.5X - 1
20 cent -----(x) x 0.20 = 0.2X
The value of the 50-cent coins is $7.40 more than the value of 20-cent coins So,
0.2 X +7.40 = 0.5 X - 1
Solving the equation,
0.3X = 8.40
2X = 56
56 + 6 = 62 coins

Qt:2

No of blue boxes = X + 12
Red boxes = X
Each blue box contained 120 plates and each red box contained 150 cups.So,
Blue boxes = X + 12 ) x (times) 120 = (120 X + 1440 )plates
Red boxes = X x 150 = 150 X cups
There were 120 fewer plates than cups in total So,
120 X + 1560 = 150X
30X = 1560
120X = 6240
6240 + 1440 = 7680 plates

[ganchiong]

NYPS Prelim 2010 Maths P1 Q13

Answer : 1

Can someone explain to me why the answer is (1). If (1), what is the answer given in (1), is it a 4 sided figure?

TIA

[tianzhu]

Hi ABCDE


Thank you for sharing.It’s always delightful to see new volunteers in this thread.

You are able to work with algebra manipulation comfortably .For a P6 student, it’s a commendable effort.

Just curious, where did you learn your problem solving technique from? Is it from school or external tuition?

Your answers are correct.

You should do well for PSLE Maths.

Best wishes