Q&A - PSLE Math

[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\">

[tianzhu]

Hi


3 units (3/7) ------ 5+7+12 ------- 24

1 unit --------- 8

Number of pupils who like lemon tea -------2*8 ------16

Total number of pupils ------- 56

Fraction of pupils who like Fanta Grape ------- 7/56 ------1/8

Best wishes

[kyp71]

tianzhu:

Hi


3 units (3/7) ------ 5+7+12 ------- 24

1 unit --------- 8

Number of pupils who like lemon tea -------2*8 ------16

Total number of pupils ------- 56

Fraction of pupils who like Fanta Grape ------- 7/56 ------1/8

Best wishes

Hi TianZhu,

I do not understand why 3 units ------ 5+7+12 ? How did not derive on this ??

[tianzhu]

kyp71:

Hi TianZhu,

I do not understand why 3 units ------ 5+7+12 ? How did not derive on this ??

Hi

Lemon tea ------- 2/7

Coke ------- 2/7 + 5

The whole of the pie chart is 7/7 or 1 whole.

Taking out 4/7, the rest (3/7) or 3 units ------ 5+7+12

Best wishes

[kyp71]

Got it. Thanks so much !

[Michaelia0816]

kyp71:

tianzhu:

Hi


3 units (3/7) ------ 5+7+12 ------- 24

1 unit --------- 8

Number of pupils who like lemon tea -------2*8 ------16

Total number of pupils ------- 56

Fraction of pupils who like Fanta Grape ------- 7/56 ------1/8

Best wishes

Hi TianZhu,

I do not understand why 3 units ------ 5+7+12 ? How did not derive on this ??

For me, I not sure why it is 3units and how to get 5 from.