Q&A - P5 Math

[lapapillion]

After editing the question, it's okay now


I'll do it this way, which is similar to yours. But I think you should just skip the first step and go straight to the second step. The first step does not logically lead to the second step

Let x be the no. of green apples:

The average cost of all the red+green apples = 0.55
=> [Total cost of green + red apples]/total no. of apples = 0.55
=> [(x-4)(0.45)+4(0.75)]/x] = 0.55
=> x = 12

[KP2]

Hi , need help with this one . Many thanks in advance


Jim bought some chocolates and gave half to them to Ken. Ken bought some sweets and gave half of them to Jim.

Jim ate 12 sweets and Ken ate 18 chocolates. After that, the number of sweets and chocolates Jim had were in the ratio 1:7 and the number of sweets and chocolates Ken had were in the ratio 1:4.

How many sweets did Ken buy?

[Maths Hub]

KP2:

Hi , need help with this one . Many thanks in advance


Jim bought some chocolates and gave half to them to Ken. Ken bought some sweets and gave half of them to Jim.

Jim ate 12 sweets and Ken ate 18 chocolates. After that, the number of sweets and chocolates Jim had were in the ratio 1:7 and the number of sweets and chocolates Ken had were in the ratio 1:4.

How many sweets did Ken buy?

The yellow boxes refer to the unchanged quantity.
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Cheers! :salute:

[zombie]

Hello, please help me to check if my answer and solution are acceptable.

I'm a parent teaching my P5 boy maths. :scratchhead: Thanks !

If Mr Ibrahim buys 3 plates and 5 cups, he will have $6 left. If he wants to buy 5 plates and 3 cups, he will need another $4. Given that a cup costs $1.50, how much does he have?

My solution

Let x be the total amount he has
3p + 7.50 = x - 6 (x5)
5p + 4.50 = x + 4 (x3)

15p + 37.50 = 5x - 30
15p + 13.50 = 3x + 12
24.00 = 2x – 42

24 + 42 = 2x

66 ÷ 2 = x
X = 33

Answer :he has $33

[Maths Hub]

zombie:

Hello, please help me to check if my answer and solution are acceptable.

I'm a parent teaching my P5 boy maths. :scratchhead: Thanks !

If Mr Ibrahim buys 3 plates and 5 cups, he will have $6 left. If he wants to buy 5 plates and 3 cups, he will need another $4. Given that a cup costs $1.50, how much does he have?

My solution

Let x be the total amount he has
3p + 7.50 = x - 6 (x5)
5p + 4.50 = x + 4 (x3)

15p + 37.50 = 5x - 30
15p + 13.50 = 3x + 12
24.00 = 2x – 42

24 + 42 = 2x

66 ÷ 2 = x
X = 33

Answer :he has $33

Hi zombie,

Depending on your child's school, algebraic method may or may not be accepted, even though it is correct.

Allow me to offer another non-algebraic way:
By drawing models,
2 plates will cost $10 more than 2 cups.
So each plate cost $5 more than each cup,
which means the cost cost of each plate is $6.50.
Therefore, he has $6.50 X 3 + 5 X $1.50 + $6 = $33. :snuggles:

Cheers.

[YumYum]

Hi, need help with qn:


In may, the average number of participants in one pottery class was 24. In June, 5 new pottery classes were added. The average number of participants in all the pottery classes became 26. If there were 32 participants in each of the new pottery classes, find the total number of participants in all the pottery classes in June.

Thanks!

[Maths Hub]

YumYum:

Hi, need help with qn:


In may, the average number of participants in one pottery class was 24. In June, 5 new pottery classes were added. The average number of participants in all the pottery classes became 26. If there were 32 participants in each of the new pottery classes, find the total number of participants in all the pottery classes in June.

Thanks!

Total extra members from the new classes that contribute to the rise in old average --> (32 - 26) X 5 = 30
Rise in old average --> 26 - 24 = 2
Original number of classes --> 30 / 2 = 15
New number of classes --> 15 + 5 = 20
Total number of participants --> 20 X 26 = 520

Cheers.

[zombie]

This question is taken from Nanyang SA2, 2011 question 17 paper 2.

Can someone help me to solve ? Thanks !

At first, the ratio of the number of men to the number of women in a
cinema was 2:5. When 48 women and some men entered the cinema
the number of women increased by 12% and the total number of people
in the cinema increased by 20%.
(a) How many men were there at first?
(b) What percentage of the people in the cinema were men in the end?
Express your answer as a mixed number.

[dazzlego]

savoury sweet:

Hi everyone,kindly help to solve the following question. Thanks so much.


A grp of pupils claculated their average score for Science test. They noted that if anyone scored 14 marks and more, their average would be 90. If anyone scored 4 marks fewer, their average score would be 88. How many pupils are there in the grp?

Hi savoury sweet,

You can assume that the number of pupils is 1 unit
case 1: the total score -> 90 units - 14
case 2: the total score -> 88 units + 4
2 units -> 14 + 4 = 18
1 unit -> 18 ÷ 2 = 9

Cheers :celebrate:

[dazzlego]

zombie:

Hello, helping my son to solve using agebra,

can someone tell me if the answer is correct ?

Can someone suggest other method? i was taught using Algebra in the 1970s. lost touch. Thanks :roll:

Mrs Lim bought some green apples for an average cost of $0.45. However, if she exchanges 4 green apples for 4 red apples, which cost $0.75 each, the average price of each apple would be $0.55
How many apples are there altogether ?

Let the total number of apples be X
X (0.45)+ (4x 0.75) \t= 0.55 X
0.45 (X - 4) + 3.00\t= 0.55 X
0.45 X -18 + 3.00\t= 0.55 X - 0.45 X
1.2\t= 0.10 X
12\t= X
there are 12 apples altogether

Hi zombie,

Generally it is correct. However don't rush the steps and don't miss all the details (decimal points, the character (X) must be writen after the number, etc)
Let the total number of apples be X
0.45 (X - 4) + 4 x 0.75 \t= 0.55 X
0.45 (X - 4) + 3.00\t= 0.55 X
0.45 X - 1.80 + 3.00\t= 0.55 X
0.45 X + 1.20 = 0.55 X
1.20\t= 0.10 X
12\t= X
there are 12 apples altogether


Cheers :celebrate: