Q&A - P5 Math

[MathIzzzFun]

concerned1970:

MathIzzzFun:

[quote=\"concerned1970\"]Need help on several ques! Ty in advance.



3) Find the height of a triangle given that its area is 48cm2 and its base is 12 cm.

Hi

area of triangle = 1/2 x base x height... you can work out the height from here.

cheers.

Tysm for yr help. I know the formula but don't know the exact workings. Pls elaborate.[/quote]48 = 1/2 x 12 x height
height = 48/6 = 8 cm

cheers.

[concerned1970]

48 = 1/2 x 12 x height

height = 48/6 = 8 cm

cheers.[/quote]

Ty for yr help

[concerned1970]

HI. Need help on following ques.


1) Mrs Tan required 3/4 kg of flour to make 96 cookies. If she had only 5/8 of the flour. How many cookies could she make?

2) 1/4 of the pizza was given to David and 2/9 of the remainder was given to Joe. The rest was then distributed equally among 7 boys. What fraction of the pizza did each boy receive?

3) On a bus, there were 32 more females than males. At a particular bus stop, 12 females alighted from the bus and 4 males boarded the bus. There were twice as many females as males in the end.
a) What was the total number of males at the bus stop? b) How many females were there on the bus at first?

4) Gina and Mike had same amount of money. After Gina gave $42 to Mike, Mike had twice as much money as Gina. How much money did Mike have in the end?

[tianzhu]

concerned1970:

2) 1/4 of the pizza was given to David and 2/9 of the remainder was given to Joe. The rest was then distributed equally among 7 boys. What fraction of the pizza did each boy receive?

Hi

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7106/6992109780_f3eabebb85_z.jpg\">

[tianzhu]

concerned1970:

HI. Need help on following ques.

1) Mrs Tan required 3/4 kg of flour to make 96 cookies. If she had only 5/8 of the flour. How many cookies could she make?

Hi

A common multiple of 4 and 8 is 16.

12 units -------- 96
1 unit -------- 8

10 units -------- 80

She could make 80 cookies

Best wishes

[tianzhu]

concerned1970:

3) On a bus, there were 32 more females than males. At a particular bus stop, 12 females alighted from the bus and 4 males boarded the bus. There were twice as many females as males in the end.
a) What was the total number of males at the bus stop? b) How many females were there on the bus at first?

4) Gina and Mike had same amount of money. After Gina gave $42 to Mike, Mike had twice as much money as Gina. How much money did Mike have in the end?

Hi

Q3)

A neat way to use is MD.

In the end

Male passengers ------ 1 unit + 4
Female passengers ------ 1 unit + 20(32-12)

2 units + 8 --------1 unit + 20
1 unit ------12

Total number of female passengers in the bus at first ------ 1 unit + 32 -------44

For (a),we only know 4 male passengers boarded the bus at the particular bus stop.

If the question setter expected students to find out the number of male passengers in the bus after boarding, the answer is 16. (The bus will be at the bus stop before moving off to the next stop)

Q4)

A neat way is using MD.

1 unit ------ 42+42 -------84

Mike ------ 2 units ------ 168

Best wishes

[cimman]

tianzhu:

concerned1970:

2) Calvin had some marbles. He gave 63 of them to Danny and 2/5 of the remainder to Ellen. After that, he found that he still had 1/4 of his marbles left. A) What fraction of his marbles did he give to Danny? B) How many marbles did Calvin have at first?

Hi

You may work with units or MD.

¼ of marbles --------- 3 units

Total marbles -------- 12 units

7 units ------- 63
1 unit ------- 9

He gave to Danny 2/12 or 1/6 of his marbles.

Calvin had 108 (12*9) marbles at first.

Best wishes

I believe the question should be phrased: What fraction of his marbles did he give to Ellen ?

[tianzhu]

cimman:

I believe the question should be phrased: What fraction of his marbles did he give to Ellen ?

Hi

He gave to Danny 63/108 or 7/12 of his marbles.

I'll revise the earlier solution.

Thank you.

Best wishes

[concerned1970]

[quote=\"tianzhu\"][quote=\"concerned1970\"]

3) On a bus, there were 32 more females than males. At a particular bus stop, 12 females alighted from the bus and 4 males boarded the bus. There were twice as many females as males in the end.
a) What was the total number of males at the bus stop? b) How many females were there on the bus at first?


Q3)

A neat way to use is MD.

In the end

Male passengers ------ 1 unit + 4
Female passengers ------ 1 unit + 20(32-12)

2 units + 8 --------1 unit + 20
1 unit ------12

Total number of female passengers in the bus at first ------ 1 unit + 32 -------44

Hi. Sry i dun get this 2 parts. Pls elaborate. Sry to trouble u. Ty for yr efforts.

2 units + 8 --------1 unit + 20
1 unit ------12

[concerned1970]

There were 920 spectators in the sports hall watching a badminton match. After 2/5 of the children and 2/7 of the adults left the hall, the number of children and the number of adults remaining in the hall were the same. a) How many children remained in the sports hall? b) How many adults were there in the sports hall at first?