Q&A - P5 Math

[carol73]

tianzhu:

carol73:

Wilson spent equal amounts of money on 5 exercise books and 7 pencils. Each exercise book cost 30cents more than each pencil. How much did Wilson spend altogether?

Hi

It helps to draw some simple diagram.

Cost of 7 pencils ------- Cost of 5 exercise books

Let cost of 1 pencil ------ 1 unit

Hence, cost of 1 exercise book ------- 1 unit + 30

7 units ------- (1 unit + 30)*5

7 units ------- 5 units +150

2 units ------ 150

1unit ------- 75

7 units ------- 525

Amount spend altogether -------- 525*2 ------- 1050 ------- $10.50

Best wishes

thanks

[amaizziq]

Hi… I need some help.


How do you find the sum of 11, 12, 13, 14, …, 58, 59, 60 ?

The question sounds easy but I do not know how to do it a better way instead of adding from 11 to 60 manually.

Thanks in advance!

[carol73]

After 35 kittens, some puppies and rabbits were sold, there were 65 animals left. There were thrice as many rabbits as puppies left. There were 26 fewer kittens left than the rabbits left. How many rabbits and puppies were sold? (44)

[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

[tianzhu]

carol73:

After 35 kittens, some puppies and rabbits were sold, there were 65 animals left. There were thrice as many rabbits as puppies left. There were 26 fewer kittens left than the rabbits left. How many rabbits and puppies were sold? (44)

Hi

Please check with your source. I think some information may be missing.

A similar question was discussed earlier in this thread.

A pet farm had the same number of kittens, puppies and rabbits at first. After 35 kittens, some puppies and rabbits were sold, there were 65 animals left. There were thrice as many rabbits as puppies left. There were 26 fewer kittens left than the rabbits left. How many rabbits and puppies were sold?

You may use MD.

In the end, the number of animals left is:

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

7 units ------ 65+26 ------91
1 unit ------ 13

Number of rabbits left ------ 3*13 ------ 39
Number of puppies left ------- 13

Number of kittens at first ------ 13+35 ------- 48

Number of rabbits sold ------ 48 – 39 ------ 9
Number of puppies sold ------- 48 – 13 ------ 35

The answer is (35+9) or 44

Best wishes

[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

thanks

tianzhu:

carol73:

After 35 kittens, some puppies and rabbits were sold, there were 65 animals left. There were thrice as many rabbits as puppies left. There were 26 fewer kittens left than the rabbits left. How many rabbits and puppies were sold? (44)

Hi

Please check with your source. I think some information may be missing.

A similar question was discussed earlier in this thread.

A pet farm had the same number of kittens, puppies and rabbits at first. After 35 kittens, some puppies and rabbits were sold, there were 65 animals left. There were thrice as many rabbits as puppies left. There were 26 fewer kittens left than the rabbits left. How many rabbits and puppies were sold?

You may use MD.

In the end, the number of animals left is:

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

7 units ------ 65+26 ------91
1 unit ------ 13

Number of rabbits left ------ 3*13 ------ 39
Number of puppies left ------- 13

Number of kittens at first ------ 13+35 ------- 48

Number of rabbits sold ------ 48 – 39 ------ 9
Number of puppies sold ------- 48 – 13 ------ 35

The answer is (35+9) or 44

Best wishes

[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