Q&A - P3 Math

[concerned1970]

Let me give a try :lol:

3 files = 2 books
6 files = 4 books

5 books (Draw a model of 5 units - take as 1 whole unit) + 6 files (Draw a model of 6 units - take as 1 whole unit) - $171
Therefore,
5 books, 1 whole unit = $171
5 books + 4 books = $171
9 books = $171

Therefore, the cost of 1 book is $171 / 9 = $19
5 books = 5 x $19 = $95

Sorry, I am very computer-retarded so I unable to draw out the model. Perhaps some other experts can assist you :imanangel:[/quote]

Oh thanks alot! I get it now!

[ttyh]

P3 Maths, pls help…


Using a 10cent coins, form a series of shapes with 1 coin on 1st row, 2 coins on 2nd row, 3 coins on 3rd row and so on.
i.e.

No. of rows No. of coins
1 ------- 1
2 ------- 3
3 ------- 6
4 ------- 10
5 ------- 15

How many 10 cent coins are needed to form 100 rows of coins?

(What is the forumla for thsi type of questions?)

[MathIzzzFun]

ttyh:

P3 Maths, pls help...


Using a 10cent coins, form a series of shapes with 1 coin on 1st row, 2 coins on 2nd row, 3 coins on 3rd row and so on.
i.e.

No. of rows No. of coins
1 ------- 1
2 ------- 3
3 ------- 6
4 ------- 10
5 ------- 15

How many 10 cent coins are needed to form 100 rows of coins?

(What is the forumla for thsi type of questions?)

Hi

1 row = 1
2 rows = 1+2 = 3
3 rows = 1+2+3=6
...
100 rows= 1+2+3+...+97+98+99+100=5050

cheers.

[tianzhu]

ttyh:

(What is the forumla for this type of questions?)

Hi

The formula is n(n+1)/2
The 100th term is 100(101)/2 which is 5050.

Best wishes

[concernParent777]

Hi all,


I need help in one of the math questions regarding fractions. Thanks

Edwin and Hubert have 111 marbles altogether. 1/3 of Edwin’s marbles is 5 more than 1/5 of Hubert’s marbles. How many marbles does Hubert have?

[corneyAmber]

http://i52.tinypic.com/2r2y9lk.jpg\">

[mama_10]

There were 6x as many boys as girls in a campfire. After an equal number of boys and girls join in halfway, there were twice as many boys as girls. if 168 children joined in halfway, how many boys were at the camp at first?


Nd help. Thanks!

[small]

mama_10:

There were 6x as many boys as girls in a campfire. After an equal number of boys and girls join in halfway, there were twice as many boys as girls. if 168 children joined in halfway, how many boys were at the camp at first?


Nd help. Thanks!

HTH..

http://i56.tinypic.com/1zzhx06.jpg\">

[mama_10]

small:

mama_10:

There were 6x as many boys as girls in a campfire. After an equal number of boys and girls join in halfway, there were twice as many boys as girls. if 168 children joined in halfway, how many boys were at the camp at first?


Nd help. Thanks!

HTH..

http://i56.tinypic.com/1zzhx06.jpg\">

:thankyou:
Actually I solved the problem w diff method :-
Boys []+14 []+14 []+14 []+14 []+14 []+14
Girls []+14 [\t 70\t]\t\t\t\t\t\t\t\t
168 / 2 = 84\t\t\t\t\t\t\t\t
84 / 6 = 14\t\t\t\t\t\t\t\t
2 units + 14 + 14 = 70\t\t\t\t\t\t
1 unit = 21\t\t\t\t\t\t\t\t
Boys at first = 6 units x 21 = 126

[] - 1 unit

[small]

mama_10:

:thankyou:
Actually I solved the problem w diff method :-
Boys []+14 []+14 []+14 []+14 []+14 []+14
Girls []+14 [\t 70\t]\t\t\t\t\t\t\t\t
168 / 2 = 84\t\t\t\t\t\t\t\t
84 / 6 = 14\t\t\t\t\t\t\t\t
2 units + 14 + 14 = 70\t\t\t\t\t\t
1 unit = 21\t\t\t\t\t\t\t\t
Boys at first = 6 units x 21 = 126

[] - 1 unit

Hi mama_10,

Can you please elaborate on how you got to:

2 units + 14 + 14 = 70

Thanks.