Q&A - PSLE Math

[MathIzzzFun]

notfreemom:

Hi,

I need help for this question.
Red Swastika Prelim 2012
Paper 2 Q 15.

Eugene, Freddy and George had some playing cards. Freddy had 200 more playing cards than Eugene. Geroge had 3/4 the number of cards Freddy had. After George lost 1/6 of his cards to Eugene, he had 320 fewer cards than Eugene. What was the ratio of the number of cards Eugene had to the number of cards Freddy had to the number of cards George had in the end?

My dd asnwer is 61:72:45 but the asnwer given is 97:104:65.
Thanks.

Hi

At first:
Eugene --> 8 units
Freddy --> 8 units + 200
George --> 6 units + 150 ----- 1/6 --> 1u + 25

after George lost 1/6 of his cards to Eugene,
Eugene --> 9 units + 25
Freddy --> 8 units + 200
George --> 5 units + 125

George had 320 cards fewer than Eugene
5 units + 125 + 320 = 9 units + 25
1 unit --> 105

In the end,
Eugene --> 970
Freddy --> 1040
George --> 650

ratio Eugene : Freddy : George = 97 : 104 : 65

cheers.

[notfreemom]

Thanks mathizzzfun and Tianzhu.

I knew my mistake now.
Thanks again.

[notfreemom]

Please help.

Red Swastika Prelim 2012
Paper 2 Q 17.
A shopkeeper had some blue and red pens in his book shop. There were twice as many red pens as blue pens. The shopkeeper sold the pens in bundles of 2 red pens and 3blue pens. After selling all the blue pens, he still had 120 red pens left. How many pens did he have in his bookshop at first?

Answer 270
thanks.

[notfreemom]

notfreemom:

Please help.

Red Swastika Prelim 2012
Paper 2 Q 17.
A shopkeeper had some blue and red pens in his book shop. There were twice as many red pens as blue pens. The shopkeeper sold the pens in bundles of 2 red pens and 3blue pens. After selling all the blue pens, he still had 120 red pens left. How many pens did he have in his bookshop at first?

Answer 270
thanks.

Oh I just managed to figure it myself. Thanks.

[dicoyote]

The cost of 3 apples is the same as that of 2 oranges. The total cost of 4 apples and 3 oranges is $3.40. Mrs Tan bought 7 apples and 5 oranges. How much did she pay for apples and oranges altogether?


I have the answer, which is $5.80, not able to work it out though, thanks in advance

[MathIzzzFun]

dicoyote:

The cost of 3 apples is the same as that of 2 oranges. The total cost of 4 apples and 3 oranges is $3.40. Mrs Tan bought 7 apples and 5 oranges. How much did she pay for apples and oranges altogether?


I have the answer, which is $5.80, not able to work it out though, thanks in advance

Hi

3 apples = 2 oranges --> 6 units

1 apple --> 2 units
1 orange --> 3 units

4 apples + 3 oranges --> 8 units + 9 units = 17 units
17 units --> $ 3.40
1 unit --> $0.20

7 apples + 5 oranges --> 14 units + 15 units = 29 units --> $ 5.80

cheers.

[AJH]

Hi.


In January, 70% of the pupils in a private school were girls and the rest were boys.
In March, 525 more pupils joined the private school and the percentage of girls increased to 80% while the number of boys tripled. How many girls joined the private school in March?

Is the ans. 75?

Thank you.

[tianzhu]

AJH:

Hi.


In January, 70% of the pupils in a private school were girls and the rest were boys.
In March, 525 more pupils joined the private school and the percentage of girls increased to 80% while the number of boys tripled. How many girls joined the private school in March?

Is the ans. 75?

Thank you.

Hi

I think the answer is 435 girls.

January

Boys ------ 3 units
Girls ------ 7 units

March

Boys ------ 9 units (tripled) ------ 20%
Girls ------ 36 units ------- 80%

45 – 10 -------- 35

35 units ------- 525

1 unit ------- 15

Increase in units for girls in March ------- 36 – 7 ------- 29

Number of girls who joined in March ------ 29*15 ------- 435

Best wishes

[MathIzzzFun]

AJH:

Hi.


In January, 70% of the pupils in a private school were girls and the rest were boys.
In March, 525 more pupils joined the private school and the percentage of girls increased to 80% while the number of boys tripled. How many girls joined the private school in March?

Is the ans. 75?

Thank you.

Hi

At first,

Girls--> 14u
Boys --> 6u
Total 20u

In Mar,
Boys --> 18u --- 20%
Total number of girls & boys in Mar --> 100/20 * 18u =90u, total joined in Mar --> 70u
Girls ---> 72u, girls joined in Mar --> 58u

70u--> 525
58*525/70 =435

435 girls joined in Mar.

cheers.

[kyp71]

Can someone please help to solve the below pie chart problem. http://i45.tinypic.com/264s8ra.jpg\">