Q&A - P5 Math

[verykiasumummy]

Udon:

verykiasumummy,


Thank you...

welcomed.. just offering help...

[ozora]

will need some help in the following questions:

1) Sean had twice as much money as George. After George spent $20 and Sean got another $50, Sean had 5 times as much as George. How much did Sean have at first? is the answer $100?

2) A bag consists of red, blue, green and white marbles. 40% of the marbles are red. The number of blue marbles is 3/5 the number of red marbles.
The ratio of the number of green to white marble is 3:2. There were 460 more red than green marbles.
How many marbles are there in the bag?
kinda of stuck using ratio with repeated identity.

[MathIzzzFun]

ozora:

will need some help in the following questions:

1) Sean had twice as much money as George. After George spent $20 and Sean got another $50, Sean had 5 times as much as George. How much did Sean have at first? is the answer $100?

2) A bag consists of red, blue, green and white marbles. 40% of the marbles are red. The number of blue marbles is 3/5 the number of red marbles.
The ratio of the number of green to white marble is 3:2. There were 460 more red than green marbles.
How many marbles are there in the bag?
kinda of stuck using ratio with repeated identity.

1)
At first, Sean : George --> 2u : 1u
In the end, Sean : George --> 2u + $50 : 1u - $20 = 5 : 1

equalize/cross-multiply --> 2u + $50 = 5u - $100
1u --> $50
At first, Sean --> $100

2)
red : blue = 40% : 3/5 x 40% = 40% : 24% (total 64%) = 5 : 3
green : white (total = 100% -64% = 36%)
= 3 : 2
= 3/5 x 36% : 2/5 x 36%
= 21.6% : 14.4%

460 more red than green:
40% - 21.6% = 18.4% --> 460
1% --> 25
100% --> 2500
Total number of marbles = 2500
(red = 1000, white = 600, green = 540, white = 360)

cheers.

[ozora]

MathIzzzFun:

ozora:

will need some help in the following questions:

1) Sean had twice as much money as George. After George spent $20 and Sean got another $50, Sean had 5 times as much as George. How much did Sean have at first? is the answer $100?

2) A bag consists of red, blue, green and white marbles. 40% of the marbles are red. The number of blue marbles is 3/5 the number of red marbles.
The ratio of the number of green to white marble is 3:2. There were 460 more red than green marbles.
How many marbles are there in the bag?
kinda of stuck using ratio with repeated identity.

1)
At first, Sean : George --> 2u : 1u
In the end, Sean : George --> 2u + $50 : 1u - $20 = 5 : 1

equalize/cross-multiply --> 2u + $50 = 5u - $100
1u --> $50
At first, Sean --> $100

2)
red : blue = 40% : 3/5 x 40% = 40% : 24% (total 64%) = 5 : 3
green : white (total = 100% -64% = 36%)
= 3 : 2
= 3/5 x 36% : 2/5 x 36%
= 21.6% : 14.4%

460 more red than green:
40% - 21.6% = 18.4% --> 460
1% --> 25
100% --> 2500
Total number of marbles = 2500
(red = 1000, white = 600, green = 540, white = 360)

cheers.

Thanks

[Dad8282]

Hi, need help with the following Q:


Catholic High SA2 2011 P2:
Q18. A bag contains some red, blue, green and white marbles. 40% of the marbles are red. The number of blue marbles is 3/5 the number of red marbles. The ratio of the number of green marbles to white marbles is 3:2. There were 460 more red marbles than green marbles. How many marbles are there in the bag?
Please solve using unit method.
Thanks!

[savoury sweet]

dazzlego:

savoury sweet:

Hi everyone,kindly help to solve the following question. Thanks so much.


A grp of pupils claculated their average score for Science test. They noted that if anyone scored 14 marks and more, their average would be 90. If anyone scored 4 marks fewer, their average score would be 88. How many pupils are there in the grp?

Hi savoury sweet,

You can assume that the number of pupils is 1 unit
case 1: the total score -> 90 units - 14
case 2: the total score -> 88 units + 4
2 units -> 14 + 4 = 18
1 unit -> 18 ÷ 2 = 9

Cheers :celebrate:

Thanks so much Dazzlego . have a nice day ahead

[dazzlego]

savoury sweet:

dazzlego:

[quote=\"savoury sweet\"]Hi everyone,kindly help to solve the following question. Thanks so much.


A grp of pupils claculated their average score for Science test. They noted that if anyone scored 14 marks and more, their average would be 90. If anyone scored 4 marks fewer, their average score would be 88. How many pupils are there in the grp?

Hi savoury sweet,

You can assume that the number of pupils is 1 unit
case 1: the total score -> 90 units - 14
case 2: the total score -> 88 units + 4
2 units -> 14 + 4 = 18
1 unit -> 18 ÷ 2 = 9

Cheers :celebrate:

Thanks so much Dazzlego . have a nice day ahead [/quote]You are very welcome. And Thanks

[dazzlego]

Dad8282:

Hi, need help with the following Q:


Catholic High SA2 2011 P2:
Q18. A bag contains some red, blue, green and white marbles. 40% of the marbles are red. The number of blue marbles is 3/5 the number of red marbles. The ratio of the number of green marbles to white marbles is 3:2. There were 460 more red marbles than green marbles. How many marbles are there in the bag?
Please solve using unit method.
Thanks!

Hi Dad8282,

It is a bit complicated. I'll try my best to explain it here. I suppose that ratio method is alright to use since it is P5
I assume red to be 40 and the total to be 100
B:R = 3:5 = 24:40 --> G and W must be total up to 36
And since G:W = 3:2, total of G and W is 5
Therefore both sides must be multiplied by 5 and 36 accordingly
B:R = 24:40 = 120:200
G:W = 3:2 = 108:72

R is 92 units more than G
1 unit --> 460 ÷ 92 = 5
500 units --> 500 × 5 = 2500

[Dad8282]

Hi dazzlego,


Thank you for your explanation. I get it now, my solution:

R:B+G+W
2:3
10:15
50:75

B:R
3:5
6:10
30:50

G:W
3:2
27:18

23u - 460
1u - 460/23 = 20
125u - 20 x 125 = 2500

Cheers,

[dazzlego]

Dad8282:

Hi dazzlego,


Thank you for your explanation. I get it now, my solution:

R:B+G+W
2:3
10:15
50:75

B:R
3:5
6:10
30:50

G:W
3:2
27:18

23u - 460
1u - 460/23 = 20
125u - 20 x 125 = 2500

Cheers,

Your welcome.

And it looks like I was too hastily assuming the red to be 40 :oops: