Q&A - PSLE Math

[keinic]

small:

Hi.

HTH..

a) 1 minute after the tap in Tank X is turned on means TanK Y was filled for 5 minutes.

Tank Y ---- 5 x (26.7-1.2) = 127.5 litres

b)
Before tap on for Tank X, Tank Y was on for 4 mins:
Volume difference between Tank Y and Tank X ----- (25.5 x 4) - 40 = 62 litres

We will need to fill up the gap between Tank X and Tank Y, so when Tank Y is 146 litres more than Tank X, the gap is :

146 - 62 = 84 litres

After tap on for Tank X :
Volume difference between Tank X and Tank Y in every 1 minute ----- (25.5 - 18.5) = 7 litres

84 / 7 = 12 mins

Hi small

Thanks so much for the detailed explanation. Initially, my own answer worked out for part b. was 16 mins i.e. 4mins + 12 mins, as I thought we had to include the 4 mins that Tank Y was turned on which contributed to the 62 litres difference . However, the model answer given was also 12 mins, the same as what you've worked out. I do agree with the answer now after looking at your detailed solution.
Thanks very much for your help. Cheers!

[small]

Hi Keinic,


You are welcome.

[beanbear]

Hi Can someone provide a model method for the following problem sum. I also have a question regarding the interpretation of certain words in the question.


4 children shared a box of chocolate bars. The first child took 1/2 of the total bars of chocolate and 1/2 of a chocolate bar. The second child took 1/2 of the remaining bars and 1/2 of a chocolate bar. The third child took 1/2 of the remaining bars and 1/2 of a chocolate bar. The fourth child took the remaining 7 bars.
(A) How many bars of chocolate were there? Ans key: 63
(B) How many bars of chocolate did the third child get? Ans key: 8

As I was working through, I was wondering about what to do with the 1/2 chocolate bar after the 1st child. Does the remaining 1/2 chocolate bar go to the remaining amount? Do you interpret \"the remaining bars\" as \"whole bars\" only or include the half choc bar?

[match3frog]

Hi mathizzzfun and yomamas, thank you for the solutions! Have a nice day

[tianzhu]

Hi


Use \"Work backwards\"

Hope this helps.

Best wishes

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[Michaelia0816]

Hello everyone! I need help, I am not sure of this question. I need step by step answer!

------------------------------------------------------------------------------------------------
A shopkeeper had two DVD players of the same model. He sold one of them at 40% more than the usual price and the other at 10% less than the usual price. He received a total of $330. What was the usual price of each DVD player?

[Michaelia0816]

The answer sheet said it was $150. Was it right?

[Michaelia0816]

Sorry as my teacher printed the question with the final answer beside it so I don know the statements and method!!!

[tianzhu]

Michaelia0816:

The answer sheet said it was $150. Was it right?

Hi

If answer is given as 150

150*0.9 ----- 135
150*1.4 ----- 210

Total sum ----- 345 and not 330.

If it is \"20% less than the usual price\", then 150 is correct.

Please check with your teacher.

Best wishes

[Michaelia0816]

Thank Tianzhu!