It has been a tiring day for MrFong,but before he sleeps he remembers that PSLE is coming! Therefore, he would leave you with one question to savour, and until the dreaded PSLE season rolls over, mr fong would give away one question each post (if he is generous :D)!
"It takes Suzie 7 hours to sew a dress by herself. If Rachel helps her, they will take 4 hours to sew the dress. How long will Rachel take to sew the dress by herself?"
Maths is about concepts and basics, but this one doesn't seem 'basic', does it? :)
See, MrFong always tell the students that PSLE is not "Please Stop Learning Everything", but no one believes! Lol...Mr Fong is appealing to the masses to donate knowledge generously, so Mr Fong's students will get this question, WHILE STOCKS LAST!
P.S. This kind of question always appear in the problem sums 4-mark range, so please understand it before stepping into the soccer field exam hall to score 'The Goal Called A*!"
Next up, a preview:
Do you know what is the sum of the odd numbers from 4 to 248? :P
Thursday, July 5, 2007
Inverse Functions: Now widely available at PSLE $Level! Get your copies WHILE STOCKS LAST!
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10 comments:
i cut to the chase. Answer is 9 hours.
Won't explain unless needed. =)
winston's balls,WRONG! :P
I like your new blogstyle, mrbrownish. haha.
yi sheng,thank you so much for your support! :) Haha,do you people have any solutions to the questions? Hope to get solutions in the comments page too,lol!
dudette. Rachel does 3/4 as much work or knitting or whatever as suzie in the same given time. So with a bit of brain usage, you can find the inverse ratio and you will get 9 hours.
There you go Mr Fong.
mingming: Good method, but careless mistake :( Come on, getting nearer! Haha.
Thank you mingming for answering, don't be careless ah!
suzie sews on 1/7 of the cloth in 1 hour. thats 4/28.when they both do it together, they'll sew 7/28 in 1 hour.therefore, rachel sews 7/28 - 4/28 = 3/28 of the cloth in 1 hour..
inverse that crap, and u get 28/3 hours which is, conveniently, 9, 1/3 hours!
And...good luck with your maths tuition,Mr Fong! Nice blog.
Han Jie: EXCELLENT! So clever :)
thanks for your encouragement,and thank you for your excellent explanation (that means i don't have to explain it myself :D
by any means, the addition questions are still up, do try to find the trick!Enjoy...
Have fun pursuing ur Mathematics career! A great math teacher indeed!
For Suzie:
7 hours ---- 1 dress
1 hour ---- 1/7 of dress
4 hours ---- 4/7 of dress
Thus, Rachael will sew 3/7 of the dress at the same time in 4 hours
For Rachael:
3/7 of dress --- 4 hours
1 whole dress --- 4/(3/7)
= 9 1/3 hrs
The answer for Rachael is 9 1/3 hours.
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