Q&A - P5 Math

[711mum]

MathIzzzFun:

711mum:

Appreciate it if someone could help with this qns:


Thomas can buy either 36 identical pens or 24 identical markers with the money he has. After buying 8 such markers and 12 such pens, how many more such pens can Thomas buy with the remaining money he has?

TIA

cost of 24 markers = cost of 36 pens
cost of 8 markers = cost of 12 pens

cost of (8 markers + 12 pens)
= cost of (12 pens + 12 pens)
= cost of 24 pens

36-24=12

Thomas can buy 12 more pens with remaining money.

cheers.

Thanks MathIzzzFun for the prompt reply.

Apologies, typo error it should be \"after buying 8 such markers and 15 such pens\", not 12.

I posted the qns as the answer is 9 in the answer key with the following working which I :? :

12+15=27 :scratchhead:
36-27=9

Now I got it, thanks again.

[carol73]

hi


anna had just received her salary on monday. she spent $480 on utility bills and 1/3 of the remainder on a handbag on the second day. after giving $200 to her parents on the third day. she had only a quarter of her salary left. how much was her salary?

[jieheng]

carol73:

hi


anna had just received her salary on monday. she spent $480 on utility bills and 1/3 of the remainder on a handbag on the second day. after giving $200 to her parents on the third day. she had only a quarter of her salary left. how much was her salary?

Salary

[-----480------][--1p--][------2p------]
[-----480------][--1p--][200][---1u---]
[--------------3u-------------][---1u---]

From the models ,

2p = 200 + 1u

480 + 1p + 200 = 3u
1p + 680 = 3u
2 * ( 1p + 680 ) = 2 * 3u
2p + 1360 = 6u
200 + 1u + 1360 = 6u
5u = 1560
1u = 312

Salary --> 4u = 4 * 312 = 1248

[iCreative Math]

carol73:

hi


anna had just received her salary on monday. she spent $480 on utility bills and 1/3 of the remainder on a handbag on the second day. after giving $200 to her parents on the third day. she had only a quarter of her salary left. how much was her salary?

For such questions, we always start from the last info given and work backwards from the last info to the first info given in the question.

Let the total salary be 8 units.

1/4 of the salary left ==> 2 units

gave her parents $ 200 ==> (2 units + 200)

we are told this is 2/3 of the remainder, hence 1/3 of salary spent on handbag is (1 unit + 100)

anna spent $ 480 on utilities ...

============================================

hence the full model is as follows:-

<-- $ 480 --><-- 1 unit + 100 --><-- 200 --><-- 2 units -->

<--------------- total of 6 units -------------><-- 2 units -->

6 units = $ 480 + 1 unit + $ 100 + $ 200

5 units = $ 780

1 unit = $ 156

8 units = $ 1,248

Anna's salary is $ 1,248.


Regards,

iCreative Math



Note: The first few explanatory statements are to help students understand the thinking behind the model. In examinations, only the steps below the ===== are required.

[MathIzzzFun]

carol73:

hi


anna had just received her salary on monday. she spent $480 on utility bills and 1/3 of the remainder on a handbag on the second day. after giving $200 to her parents on the third day. she had only a quarter of her salary left. how much was her salary?

using fractions..

2/3 of Remainder = 2/8 of Salary + $200
1/3 of Remainder = 1/8 of Salary + $100
3/3 Remainder --> 3/8 of Salary + $300

8/8 of salary = Remainder + $480 = 3/8 of Salary + $300 + $480
5/8 of Salary --> $780
Salary --> $780x 8/5 = $1 248

cheers.

[Man_at_work]

iCreative Math:

Your question is incomplete. It is missing one statement that usually says in total they have how many marbles or Bala has 10 more marbles than Amos, etc.

The problem-solving approach will then be as follows:

The ratios between them are 1:2, 1:4, and 2:3, i.e. total of 3 units, 5 units and 5 units respectively.

The lowest common multiple, LCM (which P5 should have learnt) for 3, 5 and 5 is 15.

We therefore start with a total of 15 units for A, B, C & D.

Amos' share compared to the rest is 1:2, hence Amos has 5 units (1/3 x 15).

Chris' share compared to the rest is 1:4,hence Chris has 3 units (1/5 x 15)

Bala's share compared to the rest is 2:3, hence Bala has 6 units (2/5 X 15)

Hence, Darren has 1 unit (15 - 5 - 3 - 6)

In practice, P5 students are not expected to be able to write these statements. These are not necessary. I have included them here to explain the steps. In practice, students need to simply draw a table and complete the table with the number of units A, B, C and D with simple calculation e.g. 1/3 X 15, 2/5 X 15, etc to show how they arrive at the number of units for each person.

Hope this this helpful.

Regards,

iCreative Math

Thanks a lot

[Man_at_work]

MathIzzzFun:

question is incomplete.. here's the approach to obtain the each's share of the marbles :

Amos's marbles --> 1/3 of total number -- Amos -> 1part, Bala+Chris+Darren-> 2parts, total -> 3 parts

Chris's marbles --> 1/5 of total number
Bala's marbles --> 2/5 of total number

1-1/3 -1/5-2/5 = 1/15

Darren's marbles --> 1/15 of total number

I believe you can work from here ..

cheers.

Thanks

[janicelhl]

hi please help:

Abdul bought 4 times as many candy bars as chocolate bars. The total mass of candy bars and chocolate bars was.1.64kg. The mass of chocolate bars was 0.84kg heavier than that of the candy bars. The mass of 1 bar of chocolate bar wad 0.228kg heavier than 1 bar of candy bar. Find the number of chocolate bars that Abdul bought.

[Jamesbond]

janicelhl:

hi please help:

Abdul bought 4 times as many candy bars as chocolate bars. The total mass of candy bars and chocolate bars was.1.64kg. The mass of chocolate bars was 0.84kg heavier than that of the candy bars. The mass of 1 bar of chocolate bar wad 0.228kg heavier than 1 bar of candy bar. Find the number of chocolate bars that Abdul bought.

1.64-0.84=0.8
0.8/2=0.4(mass of candy bars)
0.4/4=0.1(mass of one candy bar)
0.4+0.84=1.24(mass of chocolate bars)
1.24-0.1=1.14
1.14/0.228=5

[shann2]

Some ratio questions… Please help. TIA


Mr Lim gave some money to his two sons, Henry and Gary. If Henry gave $12 to Gary, they would have the same amount of money. If Gary gave $12 to Henry, the ratio of Henry’s amount to Gary’s amount would be 2 : 1. How much money did each boy have?

The ratio of the number of pens to the number of erasers in a shop was 5 : 1. When 10 pens were sold and the shopkeeper bought 10 more erasers, there is twice as many pens as erasers. How many more pens than erasers were there in the shop in the end?

In a ballroom, the ratio of the number of dancers to the number of non-dancers is 7 : 5. The ratio of the number of male dancers to the number of female dancers is 8 : 3. If 4/5 of the non-dancers are women and there are 56 male dancers, how many men and women are there in the ballroom?