Mr Fong is here today to give you what students love best: the answers! Here lies your haven of redemption!
Q1.There is a total of 56 books and pens. Each book cost $8 and each pen cost $6. Their total cost is $370. How many books and how many pens are there?
The Supposition Method
Method 1:
Suppose all the 56 were books,
56 x $8 = $448
$448- $370 = $78
$78 / (8-6) = 39 pens
56 - 39 pens = 17 books
Method 2:
Suppose all the 56 were pens,
56 x $6 = $336
$370 - $336 = $34
$34 / (8-6) = 17 books
56 - 17 books= 39 pens
BINGO!
Actually this is 1 question many people cannot handle, so please remember the working! or Mr Fong seriously gonna come after you,haha!
In the aftermath of the uproar that sounded as loud as the Tsunami due to his setting of that question, Mr Fong has finally relented and tada, here comes an easier question! :D
"A box contained 20-cent and 50-cent coins amounting to $18. The number of 20-cent coins was twice the number of 50-cent coins. How many 50-cent coins were there in the box?"
This is a test of your grouping skills, so therein lies my clue to you! This is normally a 3 mark question, so might as well get it right? :) More easy questions to come, stay tuned...
Wednesday, July 11, 2007
Nah nah nah, give you what you want OK! :P
Subscribe to:
Post Comments (Atom)
Stumble It!
14 comments:
2x20cents + 1x50cents = 90cents
18.00 = 1800 cents
1800/90 = 20
20x1 = 20 50cent coins
Ah, then, finally someone gets it correct on the first ever tag!
Good job :O keep posting!
haha i kind of remembered but got stuck... these qns looks difficult at first glance but are actually easy...
Bea: yeah you're right,esp this question is actually so easy! Haha,but PSLE can be easy at times too.. :D
brings me back to my Primary sch days
cuz i did this question
2x20cents + 1x50cents = 90cents
18.00 = 1800 cents
1800/90 = 20
20x1 = 20 50cent coins
Teacher! Teacher! Please Give me a shticker!
Jet: yeah such questions were common then. That was until MOE decided to add in questions like the marbles one, and those like the inverse functions!
thank you for your comment!
Papaya: Thank you for your answer.See,students nowadays are so clever! :D
Grouping is easy,yes? :)
Yes you get your shticker,lol.
this question was too challenging for me! thankfully there was the dedicated, sports-loving Maths tutor Mr Fong to teach me how to confidently step up to kick the PSLE away into the soccer goal, and score!
anonymous: Stop making me blush la :)
It's really EASY! I'll provide a solution below:
$18 in total, with 20-cent coins being twice the number of 50-cent coins:
d b
∫ 0.20 dx + ∫ 0.50 dx = 18.00
0 0
Since 2b = d,
2b b
∫ 0.20 dx + ∫ 0.50 dx = 18.00
0 0
therefore,
2b b
[0.2x] + [0.5x] = 18.00
0 0
simplifying:
0.4b - 0 + 0.5b - 0 = 18.00
0.9b = 18.00
b = 20
so there are 20 50-cent coins, and 2b = 40 20-cent coins! SO SIMPLE!!!!!
Hi levy: Remember that this is a PSLE question, and p5 kids can solve it.. :)
but not by integration!!!!!!!!!!!!Rawr! :)
but,thanks for trying! Mr Fong realizes that when he gives easy questions everyone comes and take a shot, but when it is difficult, Hmmm........
dude..u damn steady man, can get ready to set up ur own small business already...
haha, i mean Mr fong :p
ever thought of expanding a bit and making more money?
Mr Fong, this pen and book stuff.. i really liked. i normally run away from maths, i'm scared of it.. but seems, you are teaching this stupid student of yours in very amusing way.
i think i should join your class.
i'm linking you on my blog..
regards
Mr Fong
Post a Comment