Q&A - PSLE Math

[EconsPhDTutor]

pls help. thank you very much.

a motorcycle travelled 75km in 45 mins and later increased its speed by 20% for the next 150km. what was the average speed of the motorcycle for the whole journey?

During the first 45 mins, its average speed was 100 km/h.

We are told that for the remaining 150 km, its average speed was 120 km/h. And so it would have taken 1 hr 15 min to travel that 150 km.

Altogether, it took 2 hours to travel 225 km. And so the average speed for the whole journey was 112.5 km/h.

Hope this helps and feel free to ask for any clarifications.

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www.EconsPhDTutor.com

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[ninjamathtv]

Hi, ps help. Many thks and God Bless:)

2) In a bakery shop, there are some curry, sardine and kaya buns. There are 216 more curry than sardine buns. There is 3 times as many curry as kaya buns. There is 12% as many sardine buns as the total number of buns. How many buns are there in the bakery shop?

My solution in video. Hope you can understand.

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[questionable_i]

Hi! Can anyone help me with this question and please explain step by step. Thank you so much.

Q1) Mrs Tan bought some cups and pots in a shopping trip. The price of each cup was $3.20 while the price of each pot was $12.40. For every 4 pots bought, she was given one such cup for free. After receiving the free cups, the number of cups was 1/3 of the number of pots bought. If Mrs Tan paid a total of $2280,

(a) how much pots did she buy?
(b) how much more did she pay for the pots than the cups?

[alfretztay]

Hi! Can anyone help me with this question and please explain step by step. Thank you so much.

Q1) Mrs Tan bought some cups and pots in a shopping trip. The price of each cup was $3.20 while the price of each pot was $12.40. For every 4 pots bought, she was given one such cup for free. After receiving the free cups, the number of cups was 1/3 of the number of pots bought. If Mrs Tan paid a total of $2280,

(a) how much pots did she buy?
(b) how much more did she pay for the pots than the cups?

(a)

1 cup ------- $3.20

1 pot ------- $12.40

4 pots, 1 cup free


cups : pots

1 : 3

4 : 12



12 pots ------- 12 x $12.40 = $148.80

every 4 cups - 3 cups free = 1 cup bought

1 cup ------- $3.20

$3.20 + $148.80 = $152

$2280/$152 = 15 (sets)

15 x 12 = 180 (pots)


(b)

15 x $3.20 = $48

180 x $12.40 = $2232

$2232 - $48 = $2184


Ans : (a)180 pots; (b)$2184 more.

[alfretztay]

Hi! Can anyone help me with this question and please explain step by step. Thank you so much.

Q1) Mrs Tan bought some cups and pots in a shopping trip. The price of each cup was $3.20 while the price of each pot was $12.40. For every 4 pots bought, she was given one such cup for free. After receiving the free cups, the number of cups was 1/3 of the number of pots bought. If Mrs Tan paid a total of $2280,

(a) how much pots did she buy?
(b) how much more did she pay for the pots than the cups?

(a)

1 cup ------- $3.20

1 pot ------- $12.40

4 pots, 1 cup free


cups : pots

1 : 3

4 : 12



12 pots ------- 12 x $12.40 = $148.80

every 4 cups - 3 cups free = 1 cup bought

1 cup ------- $3.20

$3.20 + $148.80 = $152

$2280/$152 = 15 (sets)

15 x 12 = 180 (pots)


(b)

15 x $3.20 = $48

180 x $12.40 = $2232

$2232 - $48 = $2184


Ans : (a)180 pots; (b)$2184 more.

[ninjamathtv]

Hi, ps help. Many thks and God Bless:)

(3) Mrs Letilia made 45 fewer dumplings than Mrs Hagans. Mrs Hagans decided to give 20% of her dumplings to Mrs Letilia. Mrs Letilia then gave 2/3 of her dumplings to Mrs Hagans. In the end, Mrs Hagans had 69 more dumplings than Mrs Letilia. How many dumplings did Mrs Hagans give to Mrs Letilia?

My video solution to this question.

[/youtube]

[RJ_164]

Hi! Can you please help me with this question.
Please help me solve this problem.

In a concert hall, some people were standing while the rest were sitting. When the performance started, 20% of those who were standing decided to sit and 20% of those sitting decided to stand. In the end, 75% of audience were seated. How many percent of the audience were standing at first?

[questionable_i]

Hi! Can anyone help me with this question and please explain step by step. Thank you so much.

Q1) Mrs Tan bought some cups and pots in a shopping trip. The price of each cup was $3.20 while the price of each pot was $12.40. For every 4 pots bought, she was given one such cup for free. After receiving the free cups, the number of cups was 1/3 of the number of pots bought. If Mrs Tan paid a total of $2280,

(a) how much pots did she buy?
(b) how much more did she pay for the pots than the cups?

(a)

1 cup ------- $3.20

1 pot ------- $12.40

4 pots, 1 cup free


cups : pots

1 : 3

4 : 12



12 pots ------- 12 x $12.40 = $148.80

every 4 cups - 3 cups free = 1 cup bought

1 cup ------- $3.20

$3.20 + $148.80 = $152

$2280/$152 = 15 (sets)

15 x 12 = 180 (pots)


(b)

15 x $3.20 = $48

180 x $12.40 = $2232

$2232 - $48 = $2184


Ans : (a)180 pots; (b)$2184 more.

The part on:
cups : pots

1 : 3

4 : 12

Why do you need to multiply it by four? Can anyone help me to explain this? Thank you.

[Ender]

Hi! Can you please help me with this question.
Please help me solve this problem.

In a concert hall, some people were standing while the rest were sitting. When the performance started, 20% of those who were standing decided to sit and 20% of those sitting decided to stand. In the end, 75% of audience were seated. How many percent of the audience were standing at first?

This is my solution. But I'm not too sure if I read the question correctly.

Original Standing = 100u
Original sitting = 100p

Final Sitting = 80p + 20u
Final standing = 80u + 20p

Final Sitting is 75% , while final standing is 25%. That's makes those seating 3 times of those standing in the end.

80p + 20u = 3(80u + 20p) = 240u + 60p
20p = 220u , Substitute into original Sitting

Therefore original Sitting = 100p = 1100u

Total audience = 1100u + 100u = 1200u

% of original standing =100u/1200u X 100 = 8.3%

[ninjamathtv]

Hi, ps help. Many thks and God Bless:)

1) Irene, Doreen, Shawnia and Ruth made some balloons. Doreen made 252 balloons at first. Ruth donated some of her balloons and her number of balloons decreased by 20%. Irene made another 40% of her balloons. Shawnia gave away 30 fewer balloons than what Doreen had made. In the end, they had an equal number of balloons. How many balloons did they make altogether at first?

This is my step by step video solution, where I work backwards with an unknown beginning. Using bar models, the question becomes easy to understand.

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