Q&A - PSLE Math

[tianzhu]

Fat Mama:

For Q1, I'll interpret the 2 conditions separately and not 5+9 bowls. Am i correct?

Hi

I am given the understanding that you interpreted the two conditions separately for Q1. How does it compare to your interpretation for your question?

The “if” in a statement signifies the event didn’t really happen.

For questions on “double if”, students work on the assumption that those scenarios didn’t happen. The two conditions are also independent or exclusive as in Q2.

Q2) Susan has some vanilla and chocolate sweets in her bag. If she adds 20 vanilla sweets into the bag, the percentage of vanilla sweets in the bag becomes 40%. If she adds 30 chocolate sweets, there will be 70% of chocolate sweets in the bag. How many vanilla and chocolate sweets does she have? (P6 2010 SA2 River Valley P2 Q18)

However, in your question, in the second condition, the additional word another is added. What does the question setter have in mind at the moment when crafting this question?

Does it mean that first we add 20 ribbons and then we add another 60 ribbons to it?

If this is so, then we are lumping the two “if” conditions into one.

Having said that, could we use the same perspective to solve Q1?

Q1) Mrs Lim bought some bowls and plates. If she buys another 5 bowls, there are 60% as many bowls as plates. If she buys another 9 plates, there will be thrice as many plates as bowls. How many bowls did she buy? (CHS P5 SA2 2009) ----- (answer is 13)

Have some thoughts over these phrases, do they mean the same thing?

If you add 20 eggs
If you add another 20 eggs
If you add 20 more eggs

I think you need to work out the solution to Q1, and then compare it to your solution to your question to appreciate how one’s interpretation affects the answers.

Where is your question from? If it is from assessment books, I suggest you write to the publisher for clarification.

Best wishes

[Fat Mama]

My qn is from Nan Hua, P6 CA1 2011 Qn 7.

[fightingmom]

Please help:


Mrs Tan bought some fruits. 1/9 of the fruits were pears, 3/4 of the remaining fruits were oranges and the rest were mangoes. The prices of the fruits were as shown below:

Pears : $0.60 each
Oranges : $0.45 each
Mangoes : $1.50 each

She spent $19.80 on the pears and mangoes. How much did she spend on the mangoes?

[Ichigokun]

Oh my god. I just realised after going to Secondary School I forgot how to do Primary School math!! WAHAHAHA. Forgotten everything during the hols after PSLE.

[MathIzzzFun]

fightingmom:

Please help:


Mrs Tan bought some fruits. 1/9 of the fruits were pears, 3/4 of the remaining fruits were oranges and the rest were mangoes. The prices of the fruits were as shown below:

Pears : $0.60 each
Oranges : $0.45 each
Mangoes : $1.50 each

She spent $19.80 on the pears and mangoes. How much did she spend on the mangoes?

Hi

I think the $19.80 is spent on pears and oranges, otherwise Mrs Tan would have bought 1/2 a pear

1) $ 19.80 spent on pears and mangoes

number of pears, oranges and mangoes --> 1 : 6 : 2

1 pear + 2 mangoes --> $ 0.60 + $ 1.50 x 2 = $ 3.60
$ 19.80 / $ 3.60 = 5.5
number of pears --> 5.5
number of oranges --> 6 x 5.5 = 33
number of mangoes --> 5.5 x 2 = 11
amount spent on mangoes = 11 x $ 1.50 = $ 16.50

2) $ 19.80 spent on pears and oranges

1 pear + 6 oranges --> $ 0.60 + $ 0.45 x 6 = $ 3.30
$ 19.80 / $ 3.30 = 6
number of pears --> 6
number of oranges --> 6 x 6 = 36
number of mangoes --> 2 x 6 = 12
amount spent on mangoes = 12 x $ 1.50 = $ 18

cheers.

[anneshirleygilbert]

Hello tianzhu,


1) Susan has some vanilla and chocolate sweets in her bag. If she adds 20 vanilla sweets into the bag, the percentage of vanilla sweets in the bag becomes 40%. If she adds 30 chocolate sweets, there will be 70% of chocolate sweets in the bag. How many vanilla and chocolate sweets does she have? (P6 2010 SA2 River Valley P2 Q18)

My answer for the above question is 70 sweets, is it correct?

2) Mrs Lim bought some bowls and plates. If she buys another 5 bowls, there are 60% as many bowls as plates. If she buys another 9 plates, there will be thrice as many plates as bowls. How many bowls did she buy? (CHS P5 SA2 2009) ----- (answer is 13)

I can’t do the second question. My answer is a fraction, so I know it can’t be correct. Please help.

[tianzhu]

Hi anneshirleygilbert


The answers ----- Vanilla sweets: 72 and Chocolate sweets: 138.

For the question on bowls and plates, you may use MD or UM.

Due to time constraints, I’ve posted the solution using UM instead of MD.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7146/6728816353_e2a7aca824_z.jpg\">

[Bunny27]

tianzhu:

Hi anneshirleygilbert


The answers ----- Vanilla sweets: 72 and Chocolate sweets: 138.

For the question on bowls and plates, you may use MD or UM.

Due to time constraints, I’ve posted the solution using UM instead of MD.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7146/6728816353_e2a7aca824_z.jpg\">

Hi,
I'm not sure about this question....can someone help me?
Thanks !
A fruit seller had the same number of apples, oranges and pears at first. After he had 90 fruits left. There were 15 fewer pears than apples left. The number of apples left was twice as many as the number of oranges left. How many oranges did he sell?

[Bunny27]

Hi, not sure about this question…can someone help me?

Thanks !
A fruit seller had the same number of apples, oranges and pears at first. After he had 90 fruits left. There were 15 fewer pears than apples left. The number of apples left was twice as many as the number of oranges left. How many oranges did he sell?

[tianzhu]

Bunny27:

Hi,
I'm not sure about this question....can someone help me?
Thanks !
A fruit seller had the same number of apples, oranges and pears at first. After he had 90 fruits left. There were 15 fewer pears than apples left. The number of apples left was twice as many as the number of oranges left. How many oranges did he sell?

Hi

Good Morning.

I guess some information might be missing from your question.

Maybe, it might be something like this, After xx pears and some apples and oranges were sold, he had 90 fruits left.

Please check with your source again.

Best wishes