AC Lim's answer to Owen's Primary 6 Maths Data Analysis Singapore question.

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AC Lim
Ac Lim's answer
13119 answers (A Helpful Person)
Combination with every 5 min change. Hope this helps.♦
Owen
Owen
1 year ago
Thank you so much, much clearer now, but the problem is during PSLE exam, which is only last one hour plus only, I don’t think i have enough time to do this method, it time consuming, it will eat up the time to finish other questions to do… thank you so much
AC Lim
AC Lim
1 year ago
Yes. If use combination will kill time.
Likewise, you need to think this way. Only 2 hour at dance studio, each time 5 girls, total spend in studio 5×2=10 hours.
8 girls spend 10 hours.
1 girls spend 10/8= 1.25 hours = 1hr15mins
J
J
1 year ago
Yes like AC said, you should think of it like a question on average.

The only part is you need to consider the TOTAL number of hours spent dancing by the girls
J
J
1 year ago
The intervals that they change isn't really fixed also.

You can also make it like every 1 minute they change and eventually the sequence/order will repeat every 8 minutes.

Everyone will still get 75 minutes of dancing in the end.
AC Lim
AC Lim
1 year ago
To understand the concept, may be can start from easy questions.
Example: 4 students book badminton court for 1 hour. Each time 2 students play.
By intuitive, 1st 2 students played ½ hour then next 2 students played another ½ hours.
Each of them played ½ hour

By average...
2 students only play in 1 hour, total hours = 2×1 hour = 2 hours

4 students → 2 hr
1 student → 2/4 = ½ hour.
J
J
1 year ago
There is an alternative way to think about this question as well, which is fractions.

I'll give you a simpler example first.

① If there are 2 hours available to to play on 1 computer and there is only 1 girl, this girl can play for the full 2 hours.

②However, if there are 2 girls now and they have to share the time equally, then each girl can only play for ½ the total time.

2 hours × ½ = 1 hour

③ If there are 3 girls now then each girl can only play for ⅓ of the 2 hours.

2 hours × ⅓ = ⅔ hours = 40 minutes.


④If there are 2 computers now but still 3 girls, then ⅔ of the time.

2 hours × ⅔ = 1⅓ hours = 1h 20 min

⑤ If there are 4 computers now but 7 girls, then 4/7 of the time.


So, if there are 5 computers but 8 girls, each girl only gets to play ⅝ of the time.


2 hours × ⅝ = 5/4 hours = 1¼ hours

= 1 hour 15 min
AC Lim
AC Lim
1 year ago
@J Thanks for your super good examples and explanation. :)
J
J
1 year ago
Your explanation and diagram is great as well AC
Owen
Owen
1 year ago
Thank you so much, all the explaining is good, much clearer, thank you all ( J) and (AC). Thank you so much, thank all of you, clear my doubts