Q&A - P4 Math

[maggicho]

mathnoobs:

let me start off with the first question for P4, this question seems incomplete as it made no mention that the jug was full in the first place and out of the full jug, 150ml of water was poured into the kettle, could we assume that ? If the jug was not full to start with, the 420ml information would be meaningless.


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A kettle could hold 420 ml more water than a jug. When 150ml of water was poured from the jug into the kettle, there were 4 times as much water in the kettle as the jug. How much water was there in the jug at first ?

It is impossible to fill up a container when it is already full.
This Q is a modified Q but the setter did not modified properly.

[yeonee]

chloecube:

Q5)


Assuming all are goats,
65 x 4 = 260
260 – 196 = 64
Difference numbers of legs between duck and goat = 4-2 = 2
64/2 =32 ducks
65 – 32 = 33 goats

Check : 32 ducks x 2 legs = 64
33 goats x 4 legs = 132
64 + 132 = 196 legs

Q6)
Assuming all are cows,
75 x 4 = 300
300-220=80
Difference numbers of legs = 4-2 = 2
80/2=40ducks
75-40=35 cows

Check : 40 ducks x 2 legs =80
35 cows x 4 legs = 140
140+80=220 legs

Q7)
Assuming she answered all correctly:
20 x 5 = 100
100 – 79 = 21
Differences = 5+2 = 7
21 / 7 = 3 wrong answers
20 – 3 =17 correct answers

Check: 17 x 5 = 85
3 x 2 = 6
85 -6=79

Q8)

Assuming all coins are 50cents
38 x 50cents = $19
19 – 13.60 = 5.40
Differences = 50-20= 30cents
5.4/ 0.3 = 18 20cents
38 – 18 = 20 50cents
Ratio : 18 : 20
9: 10

i am stuck for Q1,4,9,
Tianshu, can help? thks!

Hi,

I don't understand why the answer to question 7 is 17. If she answered 17 correct questions and 3 wrong questions, isn't her marks 94 [(17x5) + (3x2)]?

[yeonee]

yeonee:

chloecube:

Q5)


Assuming all are goats,
65 x 4 = 260
260 – 196 = 64
Difference numbers of legs between duck and goat = 4-2 = 2
64/2 =32 ducks
65 – 32 = 33 goats

Check : 32 ducks x 2 legs = 64
33 goats x 4 legs = 132
64 + 132 = 196 legs

Q6)
Assuming all are cows,
75 x 4 = 300
300-220=80
Difference numbers of legs = 4-2 = 2
80/2=40ducks
75-40=35 cows

Check : 40 ducks x 2 legs =80
35 cows x 4 legs = 140
140+80=220 legs

Q7)
Assuming she answered all correctly:
20 x 5 = 100
100 – 79 = 21
Differences = 5+2 = 7
21 / 7 = 3 wrong answers
20 – 3 =17 correct answers

Check: 17 x 5 = 85
3 x 2 = 6
85 -6=79

Q8)

Assuming all coins are 50cents
38 x 50cents = $19
19 – 13.60 = 5.40
Differences = 50-20= 30cents
5.4/ 0.3 = 18 20cents
38 – 18 = 20 50cents
Ratio : 18 : 20
9: 10

i am stuck for Q1,4,9,
Tianshu, can help? thks!

Hi,

I don't understand why the answer to question 7 is 17. If she answered 17 correct questions and 3 wrong questions, isn't her marks 94 [(17x5) + (3x2)]?

Sorry, typo error. Should be 3x3.

[BigDevil]

yeonee:

yeonee:

[quote=\"chloecube\"]
Q7)
Assuming she answered all correctly:
20 x 5 = 100
100 – 79 = 21
Differences = 5+2 = 7
21 / 7 = 3 wrong answers
20 – 3 =17 correct answers

Check: 17 x 5 = 85
3 x 2 = 6
85 -6=79

Hi,

I don't understand why the answer to question 7 is 17. If she answered 17 correct questions and 3 wrong questions, isn't her marks 94 [(17x5) + (3x2)]?

Sorry, typo error. Should be 3x3.[/quote]This was the original question:[quote]7)In a Maths quiz, each pupil had to answer 20 questions. 5 points were given for each correct answer and 2 points were taken away from each wrong answer. Mirabel answered all questions and scored 79 points. How many questions did she answer correctly? (17) [/quote]So chloecube was correct to have (17x5) - (3x2) = 79

[Jamesbond]

1) There were 260 marbles in a box. 1/2 of the marbles were blue and 3/10 of them were green. The rest were red. How many red marbles were there?


2)What is 3/8 of 18? Express in the simplest form?(I doubt whether this is a correct questn)

PL explain in detail…Thank you…

[Herbie]

Jamesbond:

1) There were 260 marbles in a box. 1/2 of the marbles were blue and 3/10 of them were green. The rest were red. How many red marbles were there?


2)What is 3/8 of 18? Express in the simplest form?(I doubt whether this is a correct questn)

PL explain in detail...Thank you....

5/10 -blue
3/10 - green
2/10 - RED

[yeonee]

Noted. Thank you.

[babies]

Hi,


I need some help again... :oops:

1)
The cost of 2 mangoes and 1 apple is $3.40.
The cost of 1 mango and 2 apples is $2.60.
Find the cost of a mango.

2)
Jessie has a bag of balloons for her class. After giving 8 balloons to each pupil, she would have 4 balloons left. If she gives 5 balloons to everyone, she would have 58 balloons left. How many pupils are there in her class?

3)
In a quiz, 4 marks are awarded for every correct answer and 2 marks are deducted for every wrong answer given. Jenny answered a total of 50 questions. How many questions did she answer correctly if she had a score of 140 marks?

Thanks in advance!

[smartmummy]

babies:

Hi,


I need some help again... :oops:

1)
The cost of 2 mangoes and 1 apple is $3.40.
The cost of 1 mango and 2 apples is $2.60.
Find the cost of a mango.

2)
Jessie has a bag of balloons for her class. After giving 8 balloons to each pupil, she would have 4 balloons left. If she gives 5 balloons to everyone, she would have 58 balloons left. How many pupils are there in her class?

Thanks in advance!

1)
3 mangoes+3apples=$6
1mango +1 apple =$2
Apple=$0.60 (applying in 2nd en)
Mango=$1.40 (applying in first en)

[MathIzzzFun]

babies:

Hi,


I need some help again... :oops:

1)
The cost of 2 mangoes and 1 apple is $3.40.
The cost of 1 mango and 2 apples is $2.60.
Find the cost of a mango.

2)
Jessie has a bag of balloons for her class. After giving 8 balloons to each pupil, she would have 4 balloons left. If she gives 5 balloons to everyone, she would have 58 balloons left. How many pupils are there in her class?

3)
In a quiz, 4 marks are awarded for every correct answer and 2 marks are deducted for every wrong answer given. Jenny answered a total of 50 questions. How many questions did she answer correctly if she had a score of 140 marks?

Thanks in advance!

Hi

Q2.

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Q3.
For every question answered wrongly, marks lost = 4 + 2 = 6 marks
If all were correct, total marks --> 4 x 50 =200 marks.
Marks lost for wrong answers --> 200 - 140 = 60
60 / 6 = 10 --> 10 questions answered wrongly.
40 questions answered correctly.

cheers.