Q&A - PSLE Math

[tianzhu]

Recia Lim:

Please help to solve this speed question. Thanks!

Question: Mrs Tan took 40 min to walk from her home to the market. On her return journey, she took an additional 8 min. her speed on the way back was 1km/h slower. What was the distance between her home and the market?

Hi

There are a few ways to do this question.

For this question, students may get their answers quickly using GC.

Another possibility is to use inverse proportion if students are familiar with it.

Given the same distance, speed is inversely proportional to time.

Higher speed needs less time.

Lower speed leads to more time.

Time ratio

40:48 ------- 5:6

Speed ratio ------- 6:5

1 unit ------ 1 km/h

5 units ------ 5 km/h

Distance between her home and the market ------- 5*48/60 ------- 4 km

Alternatively you may use the faster speed of 6 km/h

In this case, 6*40/60 ------ 4 km.

Best wishes

[tianzhu]

Michaelia0816:

Hi! Thx you for helping my pervious question, I decided to use SL for it as I not really used to Units and Parts question, but I will try to use more of it often later on since it is common on hard question. But I still cannot get the balloons question right, can you teach me?
:thankyou:

Hi girl

Try to learn UP as it offers you another approach.

As for the ballon question, as I mentioned earlier, please check your source to ensure that the question is in order.

Best wishes

[Michaelia0816]

ok.

[2632parent]

Need help on this question


1) The cost of 3 apples is the same as the cost of 2 oranges. The total cost of 4 apples and 3 oranges is $3.40. Mrs tan bought 7 apples and 5 oranges. How much did she pay for the apples and oranges altogether?

Thank you

[tianzhu]

2632parent:

Need help on this question


1) The cost of 3 apples is the same as the cost of 2 oranges. The total cost of 4 apples and 3 oranges is $3.40. Mrs tan bought 7 apples and 5 oranges. How much did she pay for the apples and oranges altogether?

Thank you

Hi

You may use MD or work with units.

1 apple ----- 2 units

1 orange ----- 3 units

4*2 + 3*3 ------- 17 units

17 units ------- 340

1 unit ------ 20

Mrs Tan bought 7 apples and 5 oranges.

7*2 + 5*3 ------ 29 units

29*20 ------ 580

She paid $5.80

Best wishes

[2632parent]

Thank you councillor for your speedy reply, sorry I have another question for you.


1) Packet A, Packet B and Packet C each contained some salt. At first, there were 200g more salt in Packet A than Packet b. Packet C had 3/4 of the amount of salt in Packet A. After 1/8 of the amount of salt in Packet A was transferred to Packet B, there was 82.15g of salt in Packet B. How many percent less salt were there in Packet C than in Packet A at first?

Many many thanks

[tianzhu]

2632parent:

Thank you councillor for your speedy reply, sorry I have another question for you.


1) Packet A, Packet B and Packet C each contained some salt. At first, there were 200g more salt in Packet A than Packet b. Packet C had 3/4 of the amount of salt in Packet A. After 1/8 of the amount of salt in Packet A was transferred to Packet B, there was 82.15g of salt in Packet B. How many percent less salt were there in Packet C than in Packet A at first?

Many many thanks

Hi

Packet C had 3/4 of the amount of salt in Packet A.

A ------ 4 units

C ------- 3 units

C ------- 1 unit less than A

% ------- ¼*100% ------- 25%

Best wishes

[2632parent]

Ha! Ha! What a simple solution. get confused with all the extra information given. This is actually a 5 marks question from Nanyany primary school preliminary paper 2011. Thank you so much for your help.

[zanen]

in a test of fuel consumption, two cars, P and Q, each travel a distance of 720km.

For every litre of petrol used, Car Q travels 3km more than Car P.
Car P uses 12 litres of petrol more than Car Q.
Find the number of litres of petrol each car has used for the journey.
please help me as i am taking retake prelim tmr. thanks

[niza6666.028774hotmail.028774com]

Hi I need help on this question. Please help, thanks in advance.

Miss Lee baked some pies to sell at a fun fair. 4/5 of them were beef pies while the rest were chicken pies. At the end of the fun fair, she sold 100 chicken pies and 7/8 of the beef pies. 1/6 of the pies remained unsold. If each pie cost $2.50, how much did Miss Lee collect from the sale of the pies?