Q&A - PSLE Math

[imacsg]

Can anyone help me the below question?

Michael bought some apples and gave half of them to Jackson.
Jackson bought some pears and gave half of them to Michael.
Michael threw away 25 pears that were rotten while Jackson bought to himself another 20 apples.

After that the number of pears to apples Michael had were in the ratio 1:4 and the number of pears to apples Jackson had were in the the ratio of 1 : 2.
How many pears did Jackson buy?

Ans : 80

[MathIzzzFun]

chrisu:

Hi,

Need help for this question part (b). (a) is 75l which my daughter got it right. (b) My daughter answered 3.5 mins. but wrong.

Q) Pail A contained 20 litres of water at first. Pail B, which is empty, fills at a rate of 16 litres per minute for 4 minutes before the tap filling Pail A is turned on. Pail A fills at a rate of 11 litres per minute. Water is leaking from the bottom of Pail B at a rate of 1 litre per minute.

(a) How much water is in Pail B one minute after the tap filling Pail A is turned on?
(b) How long will it take for Pail B to contain 54 litres more water than Pail A?

Thanks.

Hi chrisu,

I did a quick check.. your daughter's answer is for the duration after Tap A is turned on, just add 4min for a total time of 7.5 min.

cheers.

[MathIzzzFun]

imacsg:

Can anyone help me the below question?

Michael bought some apples and gave half of them to Jackson.
Jackson bought some pears and gave half of them to Michael.
Michael threw away 25 pears that were rotten while Jackson bought to himself another 20 apples.

After that the number of pears to apples Michael had were in the ratio 1:4 and the number of pears to apples Jackson had were in the the ratio of 1 : 2.
How many pears did Jackson buy?

Ans : 80

Hi, pls refer to http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=27&t=6373&start=3750

cheers.

[MathIzzzFun]

wkong:

Hi All,


Need help for the following:

At a party, Mr John Doe divided all the children into groups. He could divide the children equally into groups of 3s. When he divided the children into groups of 5s, the last group was short of 2 children. When he divided the children into groups of 7s, the last group was short of 4 children. How many children were at the party? (Write down the smallest possible number.)

Thanks,
wkong

Hi wkong,

divide into group of 3 -> no remainder
divide into group of 5 -> remainder 3
divide into group of 7 -> remainder 3

So, if we take away 3 from the total number, it can be divided into groups of 3, 5, 7 with no remainder ie smallest number = LCM of 3, 5, 7 = 105

The smallest number of children in the group is 105 + 3 = 108.

Alternatively, this can also be solved using the usual \"listing\" method.

cheers.

[imacsg]

Thanks MathIzzzFun.

[wkong]

Thanks MathIzzzFun for solving my earlier question.



Hi All,

Another question that need help:

The diagram below shows 3 circles, A, B and C, overlapping one another. The total area of B and C is 4/5 that of A. Given that 1/6 of A is shaded, 1/5 of B is shaded and 1/3 of C is shaded, find the ratio of the area of A to the area of B to the area of C.
http://i56.tinypic.com/1zwgtbt.jpg\">

[MathIzzzFun]

imacsg:

Thanks MathIzzzFun.

u r welcome

cheers.

[MathIzzzFun]

wkong:

Thanks MathIzzzFun for solving my earlier question.



Hi All,

Another question that need help:

The diagram below shows 3 circles, A, B and C, overlapping one another. The total area of B and C is 4/5 that of A. Given that 1/6 of A is shaded, 1/5 of B is shaded and 1/3 of C is shaded, find the ratio of the area of A to the area of B to the area of C.
http://i56.tinypic.com/1zwgtbt.jpg\">

Hi

http://i55.tinypic.com/ilzs0l.jpg\">

cheers.

[wkong]

Thanks MathIzzzFun

[ozora]

lizawa:

ozora:

Need help in this question.

5/9 of benny's savings is the same as 2/3 of jessica's savings at first. When jessica withdraws 1/3 of her savings and Benny added $70 to his. Benny then has $190 more than Jessica.
a) how much savings does jessica have in the end?
b) if Benny withdraws half of his savings. what fraction of benny's savings is Jessica's?

Here's the solution.
http://i52.tinypic.com/fo0v81.jpg\">

thanks. so is consider equal concept? therefore have to change the numerators to the same ?