Q&A - P5 Math

[Jamesbond]

To buy a book, Ben started saving $0.40 everyday. Chloe started saving 5 days after Ben started and she saves $0.40 more than Ben everyday. When Ben saved enough money to buy the book, Chloe had already saved $14 more than him. How much does Bens book cost? :frustrated:

[PapayaDad]

After 5 day Ben already save $2 ; Chloe $0


In the end Chloe saved $14 more.

So in total Chloe need to save $16 more.
Since Chloe saved 40 cents more a day, it took Chloe 1600/40 = 40 days.

So Ben saved for 45 days.
The book cost 45 x 40 = $18

[carol73]

hi


pls advise how to draw Model for the below

mrs jeya wants to buy 10 cupcakes, but she is short of $7
if she buys 6 cupcakes, she will have $14 left, how much does each cupcakes cost?

[chloecube]

MathIzzzFun:

chloecube:

hi, need help for the followings:



container A and container B are identical. container A is 2/3 filled with water while container B is 1/3 filled with water. the ratio of the total mass of container A and its contents to the total mass of container B and its contents is 7:5. the total mass of 2 containers with their contents is 1020g. what is the mass of each empty container?

I think there is a typo error ... 3/3 should be 2/3 ?

one key strategy to use when solving problem sum is --> 'divide and conquer\" .... break up the question into sub-question and find answer to each part first.

I have added a sub-question .. hopefully this help you solve the sum..

container A and container B are identical. container A is 2/3 filled with water while container B is 1/3 filled with water. the ratio of the total mass of container A and its contents to the total mass of container B and its contents is 7:5. the total mass of 2 containers with their contents is 1020g.

a) what is the mass of each container with its contents ?
b) what is the mass of each empty container?

cheers.

hi mathizzzfun, i had followed your method of breaking up the question, the answer i got is 289g

[PapayaDad]

carol73:

hi


pls advise how to draw Model for the below

mrs jeya wants to buy 10 cupcakes, but she is short of $7
if she buys 6 cupcakes, she will have $14 left, how much does each cupcakes cost?

hope this help:

<6 cupcake>< $14><$7>

<6 cupcake><4 cupcake>

4 cupcake = 21
1 cup cake = 5.25

[MathIzzzFun]

chloecube:

MathIzzzFun:

one key strategy to use when solving problem sum is --> 'divide and conquer\" .... break up the question into sub-question and find answer to each part first.

I have added a sub-question .. hopefully this help you solve the sum..

container A and container B are identical. container A is 3/4 filled with water while container B is 1/3 filled with water. the ratio of the total mass of container A and its contents to the total mass of container B and its contents is 7:5. the total mass of 2 containers with their contents is 1020g.

a) what is the mass of each container with its contents ?
b) what is the mass of each empty container?

cheers.

hi mathizzzfun, i had followed your method of breaking up the question, the answer i got is 289g

bingo!

Total mass of Container A(empty) + contents (3/4 = 9/12) --> 7/12 x 1020g = 595g
Total mass of Container B(empty) + contents (1/3 = 4/12) --> 1020g -595g = 425g

Mass of 5/12 contents --> 595g - 425g = 170g
Mass of 1/12 of contents --> 34g
Mass of empty container --> 425g - 4 x 34g = 289g

cheers.

[chloecube]

thks Mathizzzfun

[hazelwong]

MathIzzzFun:

hazelwong:

Hi, can anyone help with this qn?

Mrs tan bought 42 apples. Each apple costs 75cents less than a pear. She spent the same amount of money on 12 pears. How much did Mrs Tan spend on buying the apples?

I managed to solve it only with algebra:
let X be price of pear
42 (X-0.75) = 12X
42X-31.50 = 12X
30X = 31.50
X = 1.05
price of apple 1.05- 0.75 = 0.3
42x0.3 = 12.60
Ans $12.60

Is using algebra ok?
Is there any other way e.g. model or units/parts?
thanks v much

cost of 42 apples = cost of 12 pears
cost of 1 apple = 12/42 cost of 1 pear = 2/7 cost of 1 pear
1 pear --> 7 units
1 apple --> 2 units

1 apple cost 75 cents less than 1 pear,
5 units --> 75 cents
1 unit --> 15 cents

cost of 1 apple --> 30 cents
cost of 42 apples --> 42 x $0.30 = $ 12.60

cheers.

:thankyou:

[pixiedust]

NPYS 2012 P5 SA1 Paper2


Q9) Any solution without using guess and check ?

http://s1197.photobucket.com/user/pixie_dust8/media/nypsq9.jpg.html

Q17) I think the answer key is wrong, hence would like to check for a 2nd opinion.
http://s1197.photobucket.com/user/pixie_dust8/media/nypsq17.jpg.html

[smartmummy]

pixiedust:

NPYS 2012 P5 SA1 Paper2



Q17) I think the answer key is wrong, hence would like to check for a 2nd opinion.
http://s1197.photobucket.com/user/pixie_dust8/media/nypsq17.jpg.html

Pls refer here,
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=68&t=25129&start=2250