Q&A - P3 Math

[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]

[small]

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?

http://s1.postimage.org/EzmwJ-0c78d7a2.jpg\">

[tianzhu]

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]

Hi small

Use Make a Supposition, you‘ll get 38 cars and 16 bicycles.

Suppose there are 54 cars, you’ll have 216 wheels

216 - 184 ----32 (add 4 to 180 to account for 4 removed bicycle wheels)
32/2 ---- 16 bicycles
54 – 16 ---- 38 cars

Check
38 *4 --- 152
16*2 ---32
Total --- 184
184 - 4 ---180

Best wishes

[small]

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?

Hi yeonee,

Another method to solve the question.

http://s1.postimage.org/ED4_9-0c78d7a2.jpg\">