Math Question

[Miniskoda]

Given

A: 1 U

B: 2 U = 3 Units

 

Therefore 1 U = 1.5 units

At first, A has 3 U = 1.5 x 3 = 4.5 Units

Total A + B = 425

4.5 Units + 4 Units = 425

8.5 Units = 425

1 unit = 50

Amt B had in the end = 3 units = 3 x 50 = $150 (ans)

 

[BlueOldMan]

Too small. Cant see anything.

 

thats true

[Rayleigh]

Morning Bro of MCF, I have another math that requires help.

 

Question: A group of student decided to share the cost of a present. When one additional student joined the group, the cost of sharing per student was reduced by $1 to $10. How many students were sharing the cost of the present initially?

 

 

I know mentally that the original number of students was 11. However, I cant think of an simple and elegant way explaining it to my P5 daughter mathematically. Can the Bros here help? Thank you in advance.

[Lala81]

 

correct. teaching is short way out. making them thk is correct n longer way

 

 

no wonder why my maths and logical reasoning is so chui. Cos i was only taught how to solve, never taught how to think

[Lala81]

Let total cost be X. Let original number of students be Y

 

X/Y+1 = $10

==> X = 10Y + 10

 

X/Y = $11 ===> X= 11Y

 

Hence Y= 10.

[Darryn]

Morning Bro of MCF, I have another math that requires help.

 

Question: A group of student decided to share the cost of a present. When one additional student joined the group, the cost of sharing per student was reduced by $1 to $10. How many students were sharing the cost of the present initially?

 

 

I know mentally that the original number of students was 11. However, I cant think of an simple and elegant way explaining it to my P5 daughter mathematically. Can the Bros here help? Thank you in advance.

 

Ask her to draw a model of the before and after situation>>> before, each student pay $11. After, each student pay $10. That means the NEW person pays $10. So the $10 distributed amongst the existing participants = 10 participants.

 

And I think you might also find that the original number of students was 10, each paying $11.

The after situation was 11 Students each paying $10

 

When doing math with my P3 daughter, always start by asking her to draw a picture of what she knows...then see if she can work out from there

[Ender]

Morning Bro of MCF, I have another math that requires help.

 

Question: A group of student decided to share the cost of a present. When one additional student joined the group, the cost of sharing per student was reduced by $1 to $10. How many students were sharing the cost of the present initially?

 

 

I know mentally that the original number of students was 11. However, I cant think of an simple and elegant way explaining it to my P5 daughter mathematically. Can the Bros here help? Thank you in advance.

 

The cost of present has to be multiple of $10 and $11 . So it's either $110, $220, $330.$440 and so on..

 

Only $110 meet the condition of difference between the initial and final number of student of 1.. i.e 10 students initially.

 

I don't know this method is consider mathematics or just plain rational.

[Manmaster]

Morning Bro of MCF, I have another math that requires help.

 

Question: A group of student decided to share the cost of a present. When one additional student joined the group, the cost of sharing per student was reduced by $1 to $10. How many students were sharing the cost of the present initially?

 

 

I know mentally that the original number of students was 11. However, I cant think of an simple and elegant way explaining it to my P5 daughter mathematically. Can the Bros here help? Thank you in advance.

Are you sure this is P5 math? It's too easy for P5. Let me show u something which is suitable for P5.

 

There are 764 marbles to be shared among a,b,c and d. If A has 20 marles lesser, B has 30 marbles more, C has to halve his marbles & D has to double his marbles, all the boys will have equal share of the marbles at the end. How many marbles does each boy have initially?

 

I can only give you a partial answer which is 1 unit = 86 marbles. I leave it for you to work it out. That's the math I had to solve for my friend's daughter.

[Manmaster]

Morning Bro of MCF, I have another math that requires help.

 

Question: A group of student decided to share the cost of a present. When one additional student joined the group, the cost of sharing per student was reduced by $1 to $10. How many students were sharing the cost of the present initially?

 

 

I know mentally that the original number of students was 11. However, I cant think of an simple and elegant way explaining it to my P5 daughter mathematically. Can the Bros here help? Thank you in advance.

My solution:

10(x+1)/x = 11

10x+10=11x

x=10

[Rayleigh]

Thanks to all bros who have replied. Have managed to explain to my daughter. I have one more Pri 5 question.

 

146 students participated in a competition. In the end, 2/3 of the boys and 3/4 of the girls managed to complete the competition. 40 students did not complete the competition. How many boys participated in the competition?

 

can anyone help? Thank you in advance.

[Darryn]

Answer...

boys = 104

Girls = 42

Remember to solve by drawing a model

B+G=40

BBBB+GGG=146

Make the leap of logic to notice that can times the first one by 3 to get boys alone...

BBB+GGG=120

By cross out the GGG and BBB you will get B=146-120

So 1B = 26

Need 4 B so is 26 x 4 which is 104

:)

[SuPerBoRed]

Answer...

boys = 104

Girls = 42

Remember to solve by drawing a model

B+G=40

BBBB+GGG=146

Make the leap of logic to notice that can times the first one by 3 to get boys alone...

BBB+GGG=120

By cross out the GGG and BBB you will get B=146-120

So 1B = 26

Need 4 B so is 26 x 4 which is 104

:)

The other way round la... girls 104.. boys 42

[Ender]

Answer...

boys = 104

Girls = 42

Remember to solve by drawing a model

B+G=40

BBBB+GGG=146

Make the leap of logic to notice that can times the first one by 3 to get boys alone...

BBB+GGG=120

By cross out the GGG and BBB you will get B=146-120

So 1B = 26

Need 4 B so is 26 x 4 which is 104

:)

I think you just used simultaneous equation. Not allowed in primary school..

[Raymondism]

Hi, I need help for a Math question for a P5 level.

 

A and B shared $425. After A spent 2/3 of his money and B spent 1/4 of his money, B had twice as much money as A. Find the amount of B had in the end.

 

Thanks in advance.

 

Anyone knows the unitary/equivalent method?

Whatis unitary and equivalent method?

Sorry no kids so dunno about this

 

Long winded way of solving:

After spending 2/3 of his money, A has 1/3 left

After spending 1/4 of his money, B has 3/4 left

3/4 of B original amount = 2 x 1/3 of A original amount

 

they share a common denominator 12

 

Therefore 9/12 B = 8/12 A, A = 9/8 B

 

Since A + B = 425,

9/8 B + B = 425

(9/8 + 8/8) B = 425

17/8 B = 425

B = 425 × 8/17

B = 200

Amount left = 3/4 B = $150

 

To check

A =225

2/3 A = $150

[Fastnfaster]

Can someone help with the following P5 question:

 

Gerald's salary of $2600 is 30% more than barry's salary. Their salaries are increased by the same percentage, and the difference in their salaries now is $780. find the percentage increase in their salary

 

thanks in advance!

Edited October 15, 2013 by Fastnfaster

[Fastnfaster]

MathAnswer2.jpg

 

[Raymondism]

Can someone help with the following P5 question:

 

Gerald's salary of $2600 is 30% more than barry's salary. Their salaries are increased by the same percentage, and the difference in their salaries now is $780. find the percentage increase in their salary

 

thanks in advance!

 

Let the increase factor be I.

 

barry salary x 130% = 2600

Barry Salary = 2000

 

2600I - 2000I =780

600I=780

I=780/600

I=780 ÷ 600 =1.3

 

their salary increased by 1.3 times

increase percentage = 30%

[Fastnfaster]

Thanks to all bros who have replied. Have managed to explain to my daughter. I have one more Pri 5 question.

 

146 students participated in a competition. In the end, 2/3 of the boys and 3/4 of the girls managed to complete the competition. 40 students did not complete the competition. How many boys participated in the competition?

 

can anyone help? Thank you in advance.

 

My method is similar to Darryn:

 

Total Boys = B+B+B ; 1/3 of boys -> B

Total Girls = G+G+G+G; 1/4 of girls -> G

 

B+G = 40

 

B+B+B+G+G+G+G = 146

 

(B+B+B+G+G+G = 3x40 = 120)

 

120 + G = 146

G = 26

 

B + 26 = 40

B = 14

 

Total boys = 14 x 3 = 42

 

cheers