Help! Difficult maths problem.

[Loki]

Any idea how to figure this out using the primary school model method:

 

There were 124 sausage and curry buns in a bakery. When 5/8 of the sausage buns and 4/7 of the curry buns were sold, the total number of sausage and curry buns left became 48. How many sausage buns were there at the bakery at first?

[SimonTan]

So easy....soho...this is much easier then the chairs question few weeks back??

 

[Loki]

So easy....soho...this is much easier then the chairs question few weeks back??

Pls help leh! I have been trying to work this out for the past 45 mins!

[Ah_cow]

Any idea how to figure this out using the primary school model method:

 

There were 124 sausage and curry buns in a bakery. When 5/8 of the sausage buns and 4/7 of the curry buns were sold, the total number of sausage and curry buns left became 48. How many sausage buns were there at the bakery at first?

8/8 sausages + 7/7 curry = 124.................(1)

(1-5/8sausages) + (1-4/7curry) = 3/8 sausages + 3/7 curry = 48

simplify it into 1 portion. trick of the question here is that they leave just nice 3/8 sausages and 3/7 curry for u to simplify it

(3/8 sausages + 3/7 curry) divided by 3 = 1/8 sausages + 1/7 curry = 48/3 = 16

(1/8 sausages + 1/7 curry) x 8 = 8/8 sausages + 8/7 curry = 16 x 8 = 128...............(2)

(2) - (1) = 128 - 124 = 1/7 curry = 4............(3)

to find total curry use (3) x 7 = 4 x 7 = 28

therefore total sausages = 124 - 28 = 96

 

[Ah_cow]

for a quicker version of my soultion

at (2) instead of times by 8 u can times by 7

7/8 sausages + 7/7 curry = 16 x 7 = 112

128 - 112 = 1/8 sausages = 12

therefore total sausages from the start = 12 x 8 = 96

[Loki]

Thanks man! You're a godsend. This is great help. How on earth are parents supposed to help their kids?

 

Can help with this one:

 

A flower shop had some lilies and roses in the ratio of 3:2. After some lilies were sold and some roses were brought in, the number of lilies decreased by 60% and the number of roses increased by 30%. If there were 105 more roses than lilies in the end, how many lilies were sold?

[Strudel-]

8/8 sausages + 7/7 curry = 124.................(1)

(1-5/8sausages) + (1-4/7curry) = 3/8 sausages + 3/7 curry = 48

simplify it into 1 portion. trick of the question here is that they leave just nice 3/8 sausages and 3/7 curry for u to simplify it

(3/8 sausages + 3/7 curry) divided by 3 = 1/8 sausages + 1/7 curry = 48/3 = 16

(1/8 sausages + 1/7 curry) x 8 = 8/8 sausages + 8/7 curry = 16 x 8 = 128...............(2)

(2) - (1) = 128 - 124 = 1/7 curry = 4............(3)

to find total curry use (3) x 7 = 4 x 7 = 28

therefore total sausages = 124 - 28 = 96

 

I thought primary school is method is the "let x be blah blah blah"?? Anyway you got the right answer.

 

I would do it as this

 

Total Sausage = S

Total Curry = C

 

Beginning,

S + C = 124 -------------(1)

 

After,

(1 - 5/8)S + (1 - 3/7)C = 48 ------------------(2)

 

(1),

S = 124 - C --------------(3)

 

Sub (3) into (2),

C = 28

 

Sub C = 28 into (1),

S = 96

 

I think this is secondary level??? Too long to remember but this is the way I would do it.....

[Mecontle]

another psle math ? no more ty , i rather sit in the loo

[Loki]

another psle math ? no more ty , i rather sit in the loo

 

this is not even PSLE. This is my kid's P5 homework!

[Moredhel]

Thanks man! You're a godsend. This is great help. How on earth are parents supposed to help their kids?

 

Can help with this one:

 

A flower shop had some lilies and roses in the ratio of 3:2. After some lilies were sold and some roses were brought in, the number of lilies decreased by 60% and the number of roses increased by 30%. If there were 105 more roses than lilies in the end, how many lilies were sold?

 

I got to check the sales invoice.

[Whitemondeo]

Thanks man! You're a godsend. This is great help. How on earth are parents supposed to help their kids?

 

Can help with this one:

 

A flower shop had some lilies and roses in the ratio of 3:2. After some lilies were sold and some roses were brought in, the number of lilies decreased by 60% and the number of roses increased by 30%. If there were 105 more roses than lilies in the end, how many lilies were sold?

 

Let my 14 yo solve your problems herewith: -

 

originally

Lilies:roses-->30:20

 

18 (60%) of lilies sold, 6(30%) roses bought

after selling/buying

lilies:roses-->12:26

 

105 flowers=26-12=14 units

 

sold=18/14 * 105 =135 flowers

[Ah_cow]

Thanks man! You're a godsend. This is great help. How on earth are parents supposed to help their kids?

 

Can help with this one:

 

A flower shop had some lilies and roses in the ratio of 3:2. After some lilies were sold and some roses were brought in, the number of lilies decreased by 60% and the number of roses increased by 30%. If there were 105 more roses than lilies in the end, how many lilies were sold?

key to solve this question is to understand the ratio 3:2

which can be translate into every 3 lilies there are 2 roses in every 5 flowers in average

therefore 2/5 lilies - 3/5 roses = 0

translate into 2/5 lilies = 3/5 roses.......(1)

next is the percentage issue, convert it into fraction

lilies decreased by 60%= 6/10 lilies sold = 4/10 lilies left

roses increased by 30% = 13/10 roses now

13/10 roses - 4/10 lilies = 105.............(2)

from (1) 4/10 lilies = 6/10 roses............(3)

substitute (3) into (2)

13/10 roses - 6/10 roses = 7/10 roses = 105....(4)

simplify (4) 1/10 roses = 15 substitute into (3) to find 4/10 lilies

(1/10 roses) x 6 = 4/10 lilies = 15 x 6 = 90

simplify into 2/10 lilies = 90 divide by 2 = 45

6/10 lilies sold= 45 x 3 = 135

[Manmaster]

key to solve this question is to understand the ratio 3:2

which can be translate into every 3 lilies there are 2 roses in every 5 flowers in average

therefore 2/5 lilies - 3/5 roses = 0

translate into 2/5 lilies = 3/5 roses.......(1)

next is the percentage issue, convert it into fraction

lilies decreased by 60%= 6/10 lilies sold = 4/10 lilies left

roses increased by 30% = 13/10 roses now

13/10 roses - 4/10 lilies = 105.............(2)

from (1) 4/10 lilies = 6/10 roses............(3)

substitute (3) into (2)

13/10 roses - 6/10 roses = 7/10 roses = 105....(4)

simplify (4) 1/10 roses = 15 substitute into (3) to find 4/10 lilies

(1/10 roses) x 6 = 4/10 lilies = 15 x 6 = 90

simplify into 2/10 lilies = 90 divide by 2 = 45

6/10 lilies sold= 45 x 3 = 135

 

Big error with your equation as you've mixed up your lilies with roses.

3/5 lilies = 2/5 roses, not 3/5 roses = 2/5 lilies

[Ehchang8]

i think pri 5 still using model to solve problem.

 

for sausages and curry problem, draw 8 squares to represent sausages, and 7 sq for curry. these 2 types of sq are not equal in size. from the drawing, u mark 3 sq sausages and 3 sq curry, and they are 48. mark again and u are left with 2 sq sausages and 1 sq curry and they are 28 (124-48-48). from the 3 sq sausages and 3 sq curry, u know 1 sq sausage and 1 sq curry is 16. minus this from the 2 sq sausage and 1 sq curry and u know 1 sq sausage is 12. so 8 sq sausages is 96.

 

for the flowers, draw 15 sq lilies and 10 sq roses. these sq are equal in size, meaning each sq represent same number of flowers, whether is rose or lily. strike off 9 sq (60%) from lilies sq, and add 3 sq (30%) to roses sq. now there are 13 roses sq and 6 lilies sq. so roses has 7 sq more, and that is equal to 105. so each sq is 15. number of lilies sold is 9 sq, which is 135.

[Badder]

Pls help leh! I have been trying to work this out for the past 45 mins!

 

seriously?

[Arowana1]

i think pri 5 still using model to solve problem.

 

for sausages and curry problem, draw 8 squares to represent sausages, and 7 sq for curry. these 2 types of sq are not equal in size. from the drawing, u mark 3 sq sausages and 3 sq curry, and they are 48. mark again and u are left with 2 sq sausages and 1 sq curry and they are 28 (124-48-48). from the 3 sq sausages and 3 sq curry, u know 1 sq sausage and 1 sq curry is 16. minus this from the 2 sq sausage and 1 sq curry and u know 1 sq sausage is 12. so 8 sq sausages is 96.

 

for the flowers, draw 15 sq lilies and 10 sq roses. these sq are equal in size, meaning each sq represent same number of flowers, whether is rose or lily. strike off 9 sq (60%) from lilies sq, and add 3 sq (30%) to roses sq. now there are 13 roses sq and 6 lilies sq. so roses has 7 sq more, and that is equal to 105. so each sq is 15. number of lilies sold is 9 sq, which is 135.

 

+1

 

there is a book in popular that teaches parents maths solutions based on grade year so tat parents do not use chim methods beyond wat is expected. cost abt 25 bucks if im not mistaken.

[Rayleigh]

+1

 

there is a book in popular that teaches parents maths solutions based on grade year so tat parents do not use chim methods beyond wat is expected. cost abt 25 bucks if im not mistaken.

 

"difficult maths made easy"