maths qns, weird

newcomer

1 Oct 07, 20:50

Mrs Lee bought a packet of rice from the grocery shop. she used 3/4 of the rice and another 1/4kg of the rick to cook lunch. Then she used 3/4 of the remaining rice to cook dinner and another 1/2kg of rice to make shushi rolls. Finally, se used the remaining 1/4kg of the rice to make rick cakes. How much rice did mrs lee buy from the grockery shop?

newcomer

1 Oct 07, 20:53

can someone come out quickly with the answer?

My answer is 13kg. But some is 16kg. They say 16kg is correct but it's actually wrong but the kids and mothers keep insisiting it's right because that's what the teacher says. Rolling Eyes

lpx88

1 Oct 07, 20:56

Originally posted by newcomer:
Mrs Lee bought a packet of rice from the grocery shop. she used 3/4 of the rice and another 1/4kg of the rice to cook lunch.

Liddat not used finish alrdy meh?

CoolMyth

1 Oct 07, 20:56

Let x be the amount of rice she bought.

(1 - 3/4)[(1 - (3/4))x - 1/4] - 1/2 - 1/4 = 0

Solve. Laughing

newcomer

1 Oct 07, 20:57

read carefully. 3/4 of the rice and another 1/4kg(or250g) of the rice. Rolling Eyes

Originally posted by lpx88:
Liddat not used finish alrdy meh?

newcomer

1 Oct 07, 20:58

thank genius. but nobody would take u for a low iq dumb arse if you kept ur mouth shut.

Originally posted by CoolMyth:
Let x be the amount of rice she bought.

(3/4)[(3/4)x + (1/4)x - 1/4] - 1/2 - 1/4 = 0

Solve.

CoolMyth

1 Oct 07, 21:02

Originally posted by newcomer:
thank genius. but nobody would take u for a low iq dumb arse if you kept ur mouth shut.

Awww.....I was trying to help. Laughing

eagle

1 Oct 07, 21:09

It's 13kg

newcomer

1 Oct 07, 21:10

DUDE YOU'RE A FARKING GENIUS. I GAVE THAT ANSWER BUT MY COUSIN AND HIS WHOLE DAMN FAMILY WON'T BELIEVE ME CUZ THEY BELIEVED THE STUPID TEACHER!!!

Originally posted by eagle:
It's 13kg

eagle

1 Oct 07, 21:12

You are giving tuition?
That means you need to strengthen your "aura". I don't know how to explain it, but if you show enough confidence, they will believe you

newcomer

1 Oct 07, 21:13

DUDE YOU'RE A FARKING GENIUS. I GAVE THAT ANSWER BUT MY COUSIN AND HIS WHOLE DAMN FAMILY WON'T BELIEVE ME CUZ THEY BELIEVED THE STUPID TEACHER!!!

Originally posted by eagle:
It's 13kg

lpx88

1 Oct 07, 21:14

Ah ic..paiseh paiseh...

Work backwards

1/4KG +1/2KG=3/4KG

3/4KG =1/4 of the last remaining

Remaining Portion = 3/4KG X 4 =3KG

3KG + 1/4KG= 3.25KG = 1/4 of the very 1st remaining

So amount she bought = 3.25KG X 4 =13KG

caleb_chiang

1 Oct 07, 21:16

newcomer

1 Oct 07, 21:17

2 teachers gave 16kg. can you believe this sh|t? wtf do these teachers come from nowadays?

sLeEpWaLkErInG

1 Oct 07, 21:17

Originally posted by newcomer:
Mrs Lee bought a packet of rice from the grocery shop. she used 3/4 of the rice and another 1/4kg of the rick to cook lunch. Then she used 3/4 of the remaining rice to cook dinner and another 1/2kg of rice to make shushi rolls. Finally, se used the remaining 1/4kg of the rice to make rick cakes. How much rice did mrs lee buy from the grockery shop?

let wgt of rice be x.

x-3/4x-(1/4)-3/4[x-(3/4x)-(1/4)]-(1/2)=1/4

x-3/4x-(1/4)-3/4x+9/16x+3/16=1/4+1/2

1/4x-3/4x+9/16x=1/4+1/2-3/16

eqn x 16

4x-12x+9x=4+8-3

x=9

wtf.. i got 9.. Confused

dunno where i wrong..

eagle

1 Oct 07, 21:20

Originally posted by newcomer:
2 teachers gave 16kg. can you believe this sh|t? wtf do these teachers come from nowadays?

Unless they see it this way:

she used 3/4 of the rice and another 1kg of the rick to cook lunch.

caleb_chiang

1 Oct 07, 21:22

I think that they are trick by the question...

must be wary of the kg... Laughing

eagle

1 Oct 07, 21:24

Originally posted by caleb_chiang:
I think that they are trick by the question...

must be wary of the kg...

Teachers are not always correct

It's always better to discuss things among your peers. Then when you are very sure, you can challenge your teachers

newcomer

1 Oct 07, 21:25

No unless they see it this way:

She used 3/4 of the rice, of which 1/4kg of it was used to cook the rice.

Is totally different from

She used 3/4 of the rice to bla bla and ANOTHER 1/4KG of the rice to bla bla

Originally posted by eagle:
Unless they see it this way:

she used 3/4 of the rice and another 1kg of the rick to cook lunch.

laurence82

1 Oct 07, 21:33

problem does not lie with maths problem

^tamago^

1 Oct 07, 22:55

Originally posted by newcomer:
Mrs Lee bought a packet of rice from the grocery shop. she used 3/4 of the rice and another 1/4kg of the rick to cook lunch. Then she used 3/4 of the remaining rice to cook dinner and another 1/2kg of rice to make shushi rolls. Finally, se used the remaining 1/4kg of the rice to make rick cakes. How much rice did Mrs Lee buy from the grocery shop?

Let x be the weight of rice Mrs Lee bought.

Â¼+Â¾(Â¼x-Â¼)+Â½+Â¼=Â¼x
13+3x=4x
x=13

^tamago^

1 Oct 07, 23:06

Originally posted by sLeEpWaLkErInG:
let wgt of rice be x.

x-3/4x-(1/4)-3/4[x-(3/4x)-(1/4)]-(1/2)=1/4

x-3/4x-(1/4)-3/4x+9/16x+3/16=1/4+1/2

1/4x-3/4x+9/16x=1/4+1/2-3/16+1/4

eqn x 16

4x-12+9x=4+8-3+4

x=13

wtf.. i got 9..

dunno where i wrong..

as above.

u can simplify Â¾(x-Â¾x-Â¼) to Â¾(Â¼x-Â¼) to reduce chance of error.

sLeEpWaLkErInG

1 Oct 07, 23:08

orrrr....

wishboy

1 Oct 07, 23:15

Originally posted by newcomer:
No unless they see it this way:

She used 3/4 of the rice, of which 1/4kg of it was used to cook the rice.

Is totally different from

She used 3/4 of the rice to bla bla and ANOTHER 1/4KG of the rice to bla bla

but the question ming ming xie zhe "another Â¼ kg" leh
ur teacher dunno how to read izzit Laughing

akinos

2 Oct 07, 00:02

13kg is the correct answer, i know this is abit too late. But u can try using the answer that the teacher said which is 16kg, and try to work it out all the way to remaining of 1/4kg rice to make rice cake, which will not be 1/4kg left as it would be 7/16 if u used the 16kg answer. thus the teacher is wrong! duh...