Tutor MathsGuru: Ask me for your burning Maths questions!
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[quote]Hi YLH88,
While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?
(a)
D : T
8 : 11
16 : 22
D : T
19 : 19
(16+22)÷2=19
3u=18
u=6
6u=36
At first, Thomas had 36 more game cards than Doran.
(b)
D : T
19:19
38: 38
D : T
3 : 1
57:19
6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
u=3
19u = 57
Thomas lost 57 more cards to Doran.[/quote]Hi Vanilla Cake,
For (a), I got the answer using the model method. For the unit method, why did you change 8:11 to 16:22 ? Why do we multiple by 2 and not 3 or 4 etc ?
For (b), why do you change from 19:19 to 38:38 and 3:1 to 57:19 ?
Thank you! -
YLH88:
Hi Vanilla Cake,[quote]Hi YLH88,
While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?
(a)
D : T
8 : 11
16 : 22
D : T
19 : 19
(16+22)÷2=19
3u=18
u=6
6u=36
At first, Thomas had 36 more game cards than Doran.
(b)
D : T
19:19
38: 38
D : T
3 : 1
57:19
6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
u=3
19u = 57
Thomas lost 57 more cards to Doran.
For (a), I got the answer using the model method. For the unit method, why did you change 8:11 to 16:22 ? Why do we multiple by 2 and not 3 or 4 etc ?
For (b), why do you change from 19:19 to 38:38 and 3:1 to 57:19 ?
Thank you![/quote]Imagine ur drawing a model.
8+11=19 is odd. do you want to draw 9 and a half units or just 38 units? -
YLH88:
Hi Vanilla Cake,[quote]Hi YLH88,
While waiting for Mathsguru's model solution, pls see whether mine using ratio is of any use or not?
(a)
D : T
8 : 11
16 : 22
D : T
19 : 19
(16+22)÷2=19
3u=18
u=6
6u=36
At first, Thomas had 36 more game cards than Doran.
(b)
D : T
19:19
38: 38
D : T
3 : 1
57:19
6u=18 [from part (a) ie 6u=36, reduce half of 36 = 18 since 19:19 has been doubled to 38:38 in part (b)]
u=3
19u = 57
Thomas lost 57 more cards to Doran.
For (a), I got the answer using the model method. For the unit method, why did you change 8:11 to 16:22 ? Why do we multiple by 2 and not 3 or 4 etc ?
For (b), why do you change from 19:19 to 38:38 and 3:1 to 57:19 ?
Thank you\tDoran : 8u + 18 = 11u – 18
3u = 36 (Additional no. of cards Thomas had at first)
(b)\tDoran had = 8u = 8 x 12 = 96
Thomas had = 11u = 11 x 12 = 132
96 + 1p = 3(132 – 1p)
4p = 300
1p = 75
Additional cards Thomas lost = 75 – 18 = 57 -
I have one question :
Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?
MTIA ! -
Emelyn:
do it step-by-step...I have one question :
Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?
MTIA !
Or
when he buy, money is being gone from his pocket (so we will minus) and when he sell, money is being earned (so we will add).
-$888 + $850 -$900 + $1000
(if you are uncomfortable with a negative integer at the front then use the \"working backwards\" )
$1000 - $900 + $850 - $888 = $62 -
CoffeeCat:
do it step-by-step...Emelyn:
I have one question :
Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?
MTIA !
Or
when he buy, money is being gone from his pocket (so we will minus) and when he sell, money is being earned (so we will add).
-$888 + $850 -$900 + $1000
(if you are uncomfortable with a negative integer at the front then use the \"working backwards\" )
$1000 - $900 + $850 - $888 = $62
The qn is actually from a colleague.
Her DD1 (P3) and DD2 (P2) teachers both said answer is $12.
I wonder why..... -
lol you very free visiting the site during work =P.
Anyway this question has gotten the attention of 2 teachers? what’s their working? -
Emelyn:
888 - 850 = 38 - lossI have one question :
Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?
MTIA !
900 - 850 = 50 -- loss
1000 - 900 = 100 -- gain
100 - 38 - 50 = $12 gain
Please see amendments that follow this thread. Correct answer is $62 gain. -
I am highly disturbed by this part
900-850=50.
Lets hope others make a comment on this. -
P5G:
Hi P5G
888 - 850 = 38 - lossEmelyn:
I have one question :
Mr Tay bought a massage chair for $888. He sold it to Mr Yeo for $850. He later bought the massage chair back from Mr Yeo for $900 and sold it to Mrs Tan for $1000. How much did Mr Tayy gain ?
MTIA !
900 - 850 = 50 -- loss
1000 - 900 = 100 -- gain
100 - 38 - 50 = $12 gain
888 - 850 = 38 - loss
900 - 850 = 50 -- loss (This line double counts the sales of 850 & purchase of 900)
1000 - 900 = 100 -- gain
100 - 38 - 50 = $12 gain (Need to remove the 50)
Should be
100 – 38 = 62 (Gain)
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