Q&A - P5 Math

[tianzhu]

carol73:

Helen and Dorothy have some marbles. If Helen gives Dorothy 15 marbles, both of them will have the same number of marbles. If Dorothy gives Helen 15 marbles, Helen will have twice as many marbles as Dorothy. How many marbles does each girl have

Hi

If Helen gives Dorothy 15 marbles, both of them will have the same number of marbles.

This means Helen has 30 more marbles than Dorothy.

Hope this helps.

Best wishes

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[tianzhu]

carol73:

hi


thanks, oh yes, I missed out the first sentence. btw can you explain why kittens is 3U-26.? I am confused with this step

Hi

There were thrice as many rabbits as puppies left. There were 26 fewer kittens left than the rabbits left.

The number of animals left are as follows

Rabbits ----- 3 units
Puppies ----- 1 unit
Kittens ------ 3 units – 26

If you draw the MD, you’ll draw 3 boxes to show the number the rabbits.
The number of kittens will be shown by a box which is shorter by the 3 boxes by 26.

Because there are 26 fewer kittens than rabbits left.

Take for example, if you have 30 rabbits , then you will have (30-26) kittens

Best wishes

[panic_mum]

Hi I have two more questions.


1) James had 3 times as many oranges as Noel. After James gave away 381 of them and Noel gave away 63, Noel had 3 times as many oranges as James. How many oranges did Noel have at first?

2) Carl and Rose had the same amount of pocket money. Each day, Carl spent $12 and Rose spent $15. When Rose had $18 left, Carl had 5 times as much money as Rose. How much was each child’s pocket money?

Thank You.

[tianzhu]

panic_mum:

1) James had 3 times as many oranges as Noel. After James gave away 381 of them and Noel gave away 63, Noel had 3 times as many oranges as James. How many oranges did Noel have at first?

Hi

You may use “Units and Parts”

Before
James: Noel ------ 3u:1u

Changes
James: Noel ------ (381):( 63)

After
James: Noel ------ 1p:3p

3u – 381 ------ 1p
(x3)
9u – 1143 ------ 3p

1u – 63 ------ 3p

Equalise the parts

9u – 1143 ------ 1u – 63

8u ------- 1080

1u ------135

Noel@first ------- 135

Best wishes

[tianzhu]

panic_mum:

2) Carl and Rose had the same amount of pocket money. Each day, Carl spent $12 and Rose spent $15. When Rose had $18 left, Carl had 5 times as much money as Rose. How much was each child's pocket money?

Hi

One way to look at this question.

Rose @left ------ 18

Carl@left ------- 90 (5*18)

Difference@left ------- 72

Difference spent per day ------ 3 (15-12)

Number of days ------- 72/3 ------- 24

Pocket money@each child ------ 24*12 + 90 ------- 378

Best wishes

[memouse]

Hi, I’m having mental block trying to solve this. Anyone can help to? Thank u so much.


Qn:
Weili used 2 strings of the same length to make 2 necklaces. For the 1st necklace, she used 2 big beads for evey 4 cm of string. For the 2nd necklace, she used 5 small beads for every 3cm of string. She used 84 more small beads than big beads.
a) Find the total number of big beads Weili used.
b) Find the total number of beads Weili used for the 2 necklaces.

[memouse]

Hi, need help to find answer to this qn. Thank u.


Qn:
Mrs Wong had some cookies to give her pupils. If she gave each of them 3 cookies each, she would have 5 left over. If she gave each pupil 4 cookies, she would need 3 more cookies. How many pupils were there?

[cookieandmonster]

Hi, need help in this question. Thank you.


Qn:
The number of books on Shelf Y was 62 more than that on Shelf X. When 31 books were transferred from Shelf X to Shelf Y, the number of books on Shelf Y became 3 times as many as the number of books on Shelf X. How many books were there on Shelf X at first?

[tianzhu]

memouse:

Hi, I'm having mental block trying to solve this. Anyone can help to? Thank u so much.


Qn:
Weili used 2 strings of the same length to make 2 necklaces. For the 1st necklace, she used 2 big beads for evey 4 cm of string. For the 2nd necklace, she used 5 small beads for every 3cm of string. She used 84 more small beads than big beads.
a) Find the total number of big beads Weili used.
b) Find the total number of beads Weili used for the 2 necklaces.

Hi

A common multiple for 4cm and 3cm is 12cm.

For a set of 12cm, there are 6 big beads and 20 small beads.

Difference per set ------ 14

Number of set of 12cm ------- 84/14 ------ 6

Number of big beads ------- 6*6 ------ 36

Total number of beads -------- 6*26 ------ 156

Best wishes

[tianzhu]

memouse:

Hi, need help to find answer to this qn. Thank u.


Qn:
Mrs Wong had some cookies to give her pupils. If she gave each of them 3 cookies each, she would have 5 left over. If she gave each pupil 4 cookies, she would need 3 more cookies. How many pupils were there?

Hi

You may use “SL” or “Excess and Shortage “

In order to give her pupils one more cookie each, Mrs Wong needs 8 (5+3) cookies

Number of pupils ------ 8/1 ------ 8

Best wishes