Q&A - P3 Math

[shirley.020816tamzil]

Hi, have a question here:


Mary had some money. She spent $38.15 on books. Her father gave her another $75 and she had a total of $155.35 in the end. How much did Sharleen have at first?

DS worked it to be $38.15+$75+$155.35=$268.50.
But I disagree, looking at the 3rd sentence, I think that the $75 is part of the $155.35 in the end, so it should be just $38.15+$155.35=$193.50.
DS argued that then $75 is not used at all which he thinks should not be the case (I sorta told him bfore that every number is important in maths problem :oops: )

Anyone can help us? Thank in adv.

[Dharma]

shirley.tamzil:

Hi, have a question here:


Mary had some money. She spent $38.15 on books. Her father gave her another $75 and she had a total of $155.35 in the end. How much did Sharleen have at first?

DS worked it to be $38.15+$75+$155.35=$268.50.
But I disagree, looking at the 3rd sentence, I think that the $75 is part of the $155.35 in the end, so it should be just $38.15+$155.35=$193.50.
DS argued that then $75 is not used at all which he thinks should not be the case (I sorta told him bfore that every number is important in maths problem :oops: )

Anyone can help us? Thank in adv.

Just need to work backwards
Amt Sharleen had at first
=$155.35 - $75 + $38.15
= $ 118.50

[shirley.020816tamzil]

Dharma:

Just need to work backwards

Amt Sharleen had at first
=$155.35 - $75 + $38.15
= $ 118.50

Oh I see, both of us are wrong. Thanks for your enlightenment... :lol:

[yeonee]

Hi, why we have to divide by 2 for this equation?



quote=\"Dharma\"]

Muffins:

Hi Dharma.

Sorry to be a buzzkill, but the actual question was 21 cm, not 210 cm....

Hi Muffins,

To climb 21cm

N x (N + 1) / 2 = 21

N x (N + 1) = 42
6 x 7 = 42
N = 6 days

By using 210cm I was trying to show that it will be easier to solve the problem by finding a pattern. The listing method will
be just too long.[/quote]

[Dharma]

yeonee:

Hi, why we have to divide by 2 for this equation?



quote=\"Dharma\"]

Muffins:

Hi Dharma.

Sorry to be a buzzkill, but the actual question was 21 cm, not 210 cm....

Hi Muffins,

To climb 21cm

N x (N + 1) / 2 = 21

N x (N + 1) = 42
6 x 7 = 42
N = 6 days

By using 210cm I was trying to show that it will be easier to solve the problem by finding a pattern. The listing method will
be just too long.

[/quote]

Hi yeonee,

Hope the link below may be useful.

http://home.covad.net/~bfjacobs/Student_Info/Math_Fun/Patterns/Triangular_Nos/lesson.html

[SPI]

Need help for this question. Thanks.


Linda used 2/3m of string to tie a pile of books and had 7/12m of string left. What was the original lenght of string she had at first?


Sorry post wrong place. Should be at P3/P4 Maths section.

[SPI]

Need help for this question. Thanks.


Linda used 2/3m of string to tie a pile of books and had 7/12m of string left. What was the original lenght of string she had at first?

[Brenda10]

SPI:

Need help for this question. Thanks.


Linda used 2/3m of string to tie a pile of books and had 7/12m of string left. What was the original lenght of string she had at first?

HI, the answer should be 1 1/4m

2/3 + 7/12 (make the base same to 12, that will be 2 x 4 and 3 x 4)
8/12 + 7/12 = 15/12
15/12 = 1 1/4

[yeonee]

Hi, I have one question:-


John had 4 times as much money as Jessie. After John received$240 and Jessie received $180, John now has twice as much money as Jessie. How much did they have altogether at first?

[small]

Much appreciated if someone can help on this question, thanks.


P4 Question:
There were 54 cars and bicycles in a car park. Someone removed 1 wheel each from 4 bicycles. As a result, there were 180 wheels left. How many cars were there? (5 marks)
[/u]