Q&A - PSLE Math

[tianzhu]

Cheerfuldad:

Q2. The ratio of the no of beads John had to the no of beads Sally had was 3:7 at first. After Sally had given some beads to John, Sally had 76 beads less than John. The ratio of john's number of beads to Sally's number of beads became 3:2.
a). How many beads did Sally give to John?
b). What percentage of her beads did Sally give to John?

Hi

A student should take note the total number of beads remains the same in the before and after scenarios.

You may work with MD or UM (Units Method).

Before
John:Sally ------ 3:7

After
John:Sally ------ 3:2 -------6:4 (Use equivalent ratios, make the total number of units the same)

2 units ------- 76
1 unit ------ 38

a) Sally gave 3 units or 3*38 (114) to John

b) 3/7*100% ------42.86%

Hope this helps.

Best wishes

[MathIzzzFun]

Cheerfuldad:

Hi all,


Please help.

Q1. Varsha had some 20-cent and 50 cent coins. 7/8 of the coins were 20 cent coins and the rest were 50 cent coins. After Varsha had spent $72.50 worth of 50 cent coins and 5/7 of the 20 cent coins, she had 2/7 of the coins left. Find the total amount of money Varsha left.

TIA

Hi

hope this helps ..

http://i51.tinypic.com/v74420.jpg\">

cheers.

[Vtsy]

Hi,


I do know the answers to the pattern by counting. I’m looking for the working to getting that or rather, the formula to find the nth term. Please advice. Thanks

[htn]

tianzhu:

htn:

Hi, please help

A pair of hamsters can produce a pair of baby hamsters every month. The baby hamsters take a month before they can reproduce another pair of baby hamsters.
How many pairs of hamsters (adult and baby) will there be by the end of 6 months??
TIA

Hi

I believe we have a question similar to yours in one of our earlier posts.

I think this is a Maths Olympiad type question and is about Fibonacci Sequence.

To begin, please follow this link to find out more about FS.
http://plus.maths.org/content/os/issue3/fibonacci/index

For P6 students, this question should come under the topic of “Number Patterns”

The sequence is as follow:
1,1,2,3,5,8,13,21,23,34,55,89 …………

Now try to understand the number sequence and look for a pattern, one will see that the next number is obtained by adding the two numbers before it.

For example,
1+1=2
1+2=3
2+3=5

Your question asks for the number at the end of 6 months, so the list is not too long, still manageable if PSLE kids choose to use “Systematic Listing”. Alternative way such as “tree” or “branching” method could also come in handy.

Hope this helps.

tianzhu
what is the answer?
Tia

[Vtsy]

Hi,


I need the working not the answer.

Thanks.

JonC:

4th = 32

12th = 192

15th = 285


6th = 60
7th = 77
8th = 96
9th = 117
10th = 140
13th = 221
14th = 252

Go figure out, don't be lazy

For your info, there is this Picture Editor which and rotate the picture to portrait.

[Vtsy]

Hhaha thanks!


It's actually the formula I need, the one needed to find the end term.

WCW:

Vtsy:

http://i55.tinypic.com/dpxow6.jpg\">

the difference between the number pattern is odd numbers...
try find the pattern and u can get ur answer easily

[Vtsy]

Yup that's what I need! Thank you so much!

WCW:

Vtsy:

Hhaha thanks!

It's actually the formula I need, the one needed to find the end term.

i get what u mean
the formula is n * (n+4)

5 = 1 * (1+4)
12 = 2 * (2+4)
21 = 3 * (3+4)
32 = 4 * (4+4)
45 = 5 * (5+4)
.
.
.
if n=12
? = 12 * (12+4) = 192
.
.
.
285 = n * (n+4)
n = 15

[tianzhu]

htn:

what is the answer?
Tia

Hi

Please follow this link.
http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/fibnat.html

It should help to answer your query.

The answer is 13.

Best wishes

[KRR]

tianzhu:

KRR:

Hi all,

I need help with this question.

On Saturday pants in a shop were sold at $30 each.
On Sunday the price of pants was reduced and number of pants sold
increased by 50% while the amount collected increased by 25%.

Find the price of pair of pants sold on Sunday.

Thanks in advance.
KRR

Hi KRR

Good Morning.

This is an interesting question. At first glance, it has too many unknowns for one to solve it. It should keep PSLE kids’ backsides glued to the chairs for some time.

You may use MD or “Number*Value”.

Due to time constraints, I shall only offer some draft this time by giving you the steps for MD.

Draw 2 boxes to show the number of pants sold on Saturday.
To use the box to show values, draw each box 30 times bigger. (30 units)
Amount collected on Saturday -------- 2*30 -------60units

Draw 3 boxes to show the number of pants sold on Sunday. (50% increase)
Amount collected on Saturday -------- 75 units (25% increase)

Price of pair of pants sold on Sunday ------- 75/3 -------25

Hope this helps.

Best wishes

Thank you so much, I was able to understand your steps and thank u once again for your time and effort.
KRR

[KRR]

WCW:

KRR:

Hi all,

I need help with this question.

On Saturday pants in a shop were sold at $30 each.
On Sunday the price of pants was reduced and number of pants sold
increased by 50% while the amount collected increased by 25%.

Find the price of pair of pants sold on Sunday.

Thanks in advance.
KRR

not so sure if can use algebra...

Let x=number of pants sold on Sat
Amount collected on Sat = 30x

Number of pants sold on Sun = 1.5x (increased by 50%)
Let y=price of pants on Sun
Amount collected on Sun = 1.5xy

Since amt collected on Sun increased by 25%
the eqn is
30x * 1.25 = 1.5xy
37.5x = 1.5xy
y = $25

Thank you very much.
KRR