Q&A - P4 Math

[Jamesbond]

htn:

Hi, need help for the following:


1) Jack is 50 years older than Alice. In 20 years' time, he will be twice as old as her. What is Alice's age now?

2)Jeffrey had $60 more than Patsy. When he gave $8 to her, he had twice as much money as she. How much money did Jeffrey have at first?


TIA

1) 50 + 20 = 70
70 + 20 = 90
90/3 = 30
30-20 = 10 Yrs old...

2) 8*2 = 16
60 - 16 = 44
44*2 = 88
88 + 8 = 96...So $96 Jeffrey had at first...

Pl correct me if I am wrong...

[Jamesbond]

Jamesbond:

A train was 2/5 full of passengers. At the first station, 1/2 of the passengers alighted and 17 people boarded the train. The train is now 1/4 full. How many passengers were there on the train at first?


Pl explain me how to solve this..

Pl help :?:

[Xiao Hu]

Jamesbond:

Jamesbond:

A train was 2/5 full of passengers. At the first station, 1/2 of the passengers alighted and 17 people boarded the train. The train is now 1/4 full. How many passengers were there on the train at first?


Pl explain me how to solve this..

Pl help :?:

This is how I solve it:
After 1/2 left, left with 1/5 full.
1/5 full + 17 =1/4 full

¼ full – 1/5 full =17
5/20 full - 4/20 full = 17
1/20 full = 17
Full \t= 17*2
\t= 340
At first, no. of passengers \t= 2/5 * 340
\t\t\t\t=136
(P4 can solve it this way at this step,
5U=340
1u=68
2u=136)

Is the answer correct?
Hope it is and useful.

Regards,
Xiaohu.

[Jamesbond]

There are a total of 28 chickens and cows in a farm. If the total number of cows legs is 46 more than the total number of chickens legs, Find the number of

a) Chickens in the farm
b) Cows in the farm.

Pl help…

[Champion]

Hi All! Needs :?: with the following three Maths Questions. Please advise with Model Drawings if possible; :thankyou:


1) Jane exchanged 12 $10-notes for $2-notes and $5-notes.
The total value of the $5-notes was 5 times the total value of the $2-notes.
How many more $5-notes than $2-notes did she get?


2) Jeremy has 8 more 20-cents coins than $1-coins.
If he has $8.80 in total, how many coins does he have altogether?


3) Gabriel, Hosea and Issac shared a birthday cake of mass 3kg.
Gabriel ate 4/15 of the cake and Hosea ate 7/11 of the remaining cake.
If Issac ate the rest of the birthday cake, what the mass of the birthday cake that Issac ate? Express your answer in its simplest form.

[kiasuMay11]

Jamesbond:

There are a total of 28 chickens and cows in a farm. If the total number of cows legs is 46 more than the total number of chickens legs, Find the number of

a) Chickens in the farm
b) Cows in the farm.

Pl help...

Guess and check. start at half of total, 28 => 14

#chick | #Cow | 2xleg | 4xleg | diff in legs
14 | 14 | 28 | 56 | 28 => not enough cow
8 | 20 | 16 | 80 | 64 => too many cow
10 | 18 | 20 | 76 | 56 => close
11 | 17 | 22 | 68 | 46 => 11 chick, 17 cow.

[kiasuMay11]

Champion:

Hi All! Needs :?: with the following three Maths Questions. Please advise with Model Drawings if possible; :thankyou:


1) Jane exchanged 12 $10-notes for $2-notes and $5-notes.
The total value of the $5-notes was 5 times the total value of the $2-notes.
How many more $5-notes than $2-notes did she get?


2) Jeremy has 8 more 20-cents coins than $1-coins.
If he has $8.80 in total, how many coins does he have altogether?


3) Gabriel, Hosea and Issac shared a birthday cake of mass 3kg.
Gabriel ate 4/15 of the cake and Hosea ate 7/11 of the remaining cake.
If Issac ate the rest of the birthday cake, what the mass of the birthday cake that Issac ate? Express your answer in its simplest form.

I only good for (3)

http://i47.tinypic.com/2wr2mio.jpg\">

1st 15 blk
shape 4 blk for 4/15
u can see 11 blk remain which tally with the denominator of 7/11
next shape 7 blk of remaining 11 blk
Thus, 4 blk left for Issac
u know total is 3kg, 3/15=> 0.2kg per unit
Therefore, Issac = 4*0.2 = 0.8kg

Hope other can help on other question with model as I would like to learn how, too

[Jamesbond]

Tan bought some fruits. 2/7 of the fruits were apples. The number of oranges was 1/4 the number of pears. What fraction of the fruits were pears?


Pl help…

[Xiao Hu]

kiasuMay11:

Jamesbond:

There are a total of 28 chickens and cows in a farm. If the total number of cows legs is 46 more than the total number of chickens legs, Find the number of

a) Chickens in the farm
b) Cows in the farm.

Pl help...

Guess and check. start at half of total, 28 => 14

#chick | #Cow | 2xleg | 4xleg | diff in legs
14 | 14 | 28 | 56 | 28 => not enough cow
8 | 20 | 16 | 80 | 64 => too many cow
10 | 18 | 20 | 76 | 56 => close
11 | 17 | 22 | 68 | 46 => 11 chick, 17 cow.

Hi Jamesbond,
Please see the Supposition method used in this similar question solved by Tianzhu.I tried to copied from an ealier post I replied before in this P4 maths forum. You can try to search it yourself with key word Supposition to see other examples.

tianzhu:

Xiao Hu:

Hi Tianzhu,
The solution pasted was removed. Can you help give the solution one more time for this Q4?

\"4)There were 50 children in Xie Ming Ming’s party. Each boy ate 10 cookies. Each girl ate 7 cookies. All the girls ate 44 more cookies than all the boys. How many more girls than boys were there? (14)\"

TIA,
Xiaohu

Hi Xiao Hu

Good Morning.

Here's an earlier slide for a similar type of questions.

The solution to Xie question.

Assume all were girls.

50*7 ------ 350
(49*7) – 10 ------ 333

For every increase of 1 boy, the difference in the number of cookies drops by 17.

350 – 44 ------ 306
306/17 ------ 18

So, we have 18 boys and 32 girls.

Hence, there are 14 more girls than boys.

Best wishes

http://farm8.staticflickr.com/7016/6828705773_53738730b6_z.jpg\">

Hi Tianzhu,
Thanks so much. This solution to me is more than just supposition strategy. This has Suppostion, Listing/Tabulating and Looking for a pattern strategies all in.

Good question from you!!

Thanks,
Xiaohu

[Jamesbond]

Wow Thank you so much for guiding me..Actually I was eager to learn some other method......simply great.... :salute: :rahrah: