Q&A - P5 Math

[swordtail]

The area of a rectangle is 180 cm square. The ratio of its length to its breadth is 5:1. What is its breadth?


I dont understand the school’s solution. Hoping that somebody can offer alternative solution or a clearer explanation. tks.

[Oracle]

Need help on this Q please:


Mr Chua has a class of less than 40 pupils. He gave all the pupils in his class some jellybeans. If he gave 5 jellybeans to each pupil, he would have 2 jellybeans left. If he gave 4 jellybeans to each pupil, he would have 38 jellybeans left.

(a) How many pupils were there in his class?
(b) How many jellybeans did Mr Chua have?

Thank you very much.

[PapayaDad]

2) Ramesh and Dominic shared a total sum of $510. After Ramesh spent 2/3 of his money and Dominic spent 1/4 of his money, Dominic had twice as much money left as Ramesh. Find the amount of money Ramesh had at first?


D at first have 8u
spent 1/4 ; left 6u

R is left with half of D ie… 3u
R at first have 9u

At first
D=8u
R=9u
total = 17u =510
u = 30

D=8x30=240
R=9x30 =270


[uuuuuu] ; [uu] => Dominic 8 units spent 2 units left 6 units
[uuu] ; [uuuuuu] => Ramesh 9 units spent 6 units left 3units

[PapayaDad]

Need help on this Q please:


Mr Chua has a class of less than 40 pupils. He gave all the pupils in his class some jellybeans. If he gave 5 jellybeans to each pupil, he would have 2 jellybeans left. If he gave 4 jellybeans to each pupil, he would have 38 jellybeans left.

(a) How many pupils were there in his class?
(b) How many jellybeans did Mr Chua have?

he gave 4 jellybeans to each pupil, he would have 38 jellybeans left.
this 38 leftover can still be distributed to the class and there will be 2 left over
38-2=36 pupils.

jellybeans = 36 x 5 + 2 = 180 + 2 = 182

check 36 x 4 = 144
182 - 144 = 38 correct

[chloecube]

Rose n Mary have some stamps, if rose give Mary 15 stamps, Mary will have thrice as many stamps as rose. If mary give rose 15 stamps, rose will have twice as many stamps as mary.how many stamps does each of them have.


is there somethig wrong with the question? i cannot seem to get the model out of Rose and Mary :scratchhead:

[PapayaDad]

3)Ali, Betty and Catty had 98 stickers altogether. After Ali gave away 5 stickers, Betty doubled her stickers and Catty bought 3 more stickers, the ratio of the stickers of Ali, Betty and Catty became 1:4:5 respectively. How many stickers did each of them have at first


1p:4p:5p

work backwards will get
1p+5 ; 2p ; 5p-3

1p+5+2p+5p-3 = 98
8p+2=98
8p=96
p=12

at first
A=1p+5=12+5=17
B=2p=24
C=5p-3=57

[carol73]

thanks

PapayaDad:

3)Ali, Betty and Catty had 98 stickers altogether. After Ali gave away 5 stickers, Betty doubled her stickers and Catty bought 3 more stickers, the ratio of the stickers of Ali, Betty and Catty became 1:4:5 respectively. How many stickers did each of them have at first

1p:4p:5p

work backwards will get
1p+5 ; 2p ; 5p-3

1p+5+2p+5p-3 = 98
8p+2=98
8p=96
p=12

at first
A=1p+5=12+5=17
B=2p=24
C=5p-3=57

[MathIzzzFun]

swordtail:

The area of a rectangle is 180 cm square. The ratio of its length to its breadth is 5:1. What is its breadth?


I dont understand the school's solution. Hoping that somebody can offer alternative solution or a clearer explanation. tks.

http://i40.tinypic.com/v83f5f.png\">

cheers.

[sokk]

MathIzzzFun:

swordtail:

The area of a rectangle is 180 cm square. The ratio of its length to its breadth is 5:1. What is its breadth?


I dont understand the school's solution. Hoping that somebody can offer alternative solution or a clearer explanation. tks.

http://i40.tinypic.com/v83f5f.png\">

cheers.

Hi,

Just feel the need to bring this up...correct me if I'm wrong


The correct way to read the units for area is 180 square cm and
not 180 cm square.

180 cm square would mean a square with sides of 180cm
while 180 square cm would mean a figure with an area of 180 square units, the units here being 1cm square unit.

Pardon me for being nosy
Just hope that we can teach our children to read the units of area correctly. Have encountered children reading it the wrong way because they see the \"cm\" coming right after the value , hence they tend to read it as \"cm square\".


Cheers!

[MathIzzzFun]

sokk:

MathIzzzFun:

[quote=\"swordtail\"]The area of a rectangle is 180 cm square. The ratio of its length to its breadth is 5:1. What is its breadth?


I dont understand the school's solution. Hoping that somebody can offer alternative solution or a clearer explanation. tks.

http://i40.tinypic.com/v83f5f.png\">

cheers.

Hi,

Just feel the need to bring this up...correct me if I'm wrong


The correct way to read the units for area is 180 square cm and
not 180 cm square.

180 cm square would mean a square with sides of 180cm
while 180 square cm would mean a figure with an area of 180 square units, the units here being 1cm square unit.

Pardon me for being nosy
Just hope that we can teach our children to read the units of area correctly. Have encountered children reading it the wrong way because they see the \"cm\" coming right after the value , hence they tend to read it as \"cm square\".


Cheers![/quote]you are right in that when reading and writing, \"we all got learn\" cm² is read/written as square cm
...however, given the limitations of the text editor in message board, most would conveniently write 180cm² as 180cm2 or the colloquial 180 cm square ...

cheers.