Q&A - PSLE Math

[tisha]

atutor2001:

tisha:

[quote]
In planning for a party, Mrs Lim bought enough satay to allow her guests an average of 25 sticks each. If 2 more people joined the party, how many fewer sticks of satay will each of her guests be given?

Can no other method that can be used?
How to do tabulation, for this problem I'm not even sure where to start. :?

This is question is an example of the superiority of algebra over heuristic (but it is too complicated for Pr. However, I think GEP can still do it) Let me first present the algebraic method then the heuristic method.

Algebraic method :
Let the no. of guests be G
Let the decrease in the average be d

Before :
No. of guests = G
Average no. of satays = 25
Total no. of satay = 25G

After :
No. of guests = (G+2)
Average no. of satays = (25-d)
Total no. of satay = (G+2)(25-d) = 25G + 50 - d(G+2)

.
.
.

My above reasonings actually comes from the algebraic solution. So algebra is a mathematical tool but models and heuristics are not. We can get the heuristic concept from algebra. Good luck![/quote]:thankyou: atutor for this solution. By the time I finished reading the solution, I couldn't even recall what the Q was? :lol:
Will read again and slowly try to chew and digest. Thanks for the detailed explaination.

BTW, if the students draw some neat columns and do a few tabulations will it fetch any marks for the method :?:

[moonee]

:?: Hi can anyone help with this P5 question?


A frog took 5 leaps forward and 6 leaps back. Next it took 7 leaps forward and 8 leaps back. Finally, it took 4 more leaps forward before stopping.

a.Did the frog stop in front of or behind its starting point?
b. How many leaps away was it from its starting point?
c. How many times did it leap over the starting point?
d. How many leaps away was the frog from the starting point when it was furthest away?


~~~~Thank You~~~~

[Cheerfuldad]

Hi all,


Please help!

Q. Tank X and Y are each filled with some water. If water from Tank Y is poured into Tank X until the water in Tank X reaches the brim, there will be 8 litres of water left in Tank Y. If water from Tank X is poured into Tank Y until the water in Tank Y reaches the brim, there will be 26 litres of water left in Tank X. The ratio of the volume of Tank X to the volume of Tank Y is 5:3. How many more litres of water are needed to fill both tanks to their brim?

[tianzhu]

moonee:

:?: Hi can anyone help with this P5 question?


A frog took 5 leaps forward and 6 leaps back. Next it took 7 leaps forward and 8 leaps back. Finally, it took 4 more leaps forward before stopping.

a.Did the frog stop in front of or behind its starting point?
b. How many leaps away was it from its starting point?
c. How many times did it leap over the starting point?
d. How many leaps away was the frog from the starting point when it was furthest away?

Hi moonee

Good Evening.

You may use a heuristics known as Draw a Diagram to have a pictorial representation of the question.

a)The frog stopped in front of its starting point.
b)It was two leaps away from the starting point.
c)4 times
d)6 leaps

If you need the diagram, please let me know. I’ll do it tomorrow.

Best wishes

[tianzhu]

Cheerfuldad:

Hi all,


Please help!

Q. Tank X and Y are each filled with some water. If water from Tank Y is poured into Tank X until the water in Tank X reaches the brim, there will be 8 litres of water left in Tank Y. If water from Tank X is poured into Tank Y until the water in Tank Y reaches the brim, there will be 26 litres of water left in Tank X. The ratio of the volume of Tank X to the volume of Tank Y is 5:3. How many more litres of water are needed to fill both tanks to their brim?

Hi Cheerfuldad

Good Evening.

There is a similar question on page 238 of this thread. You may wish to refer to it.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?p=351164

Best wishes

[atutor2001]

tisha:

BTW, if the students draw some neat columns and do a few tabulations will it fetch any marks for the method :?:

Marks will only be given if the headings of the columns are relevant. BTW this question should not be solved by listing. It is by \"matching of factors\" of the number 50.

[youngtay]

Mr Tianzhu


Thanks

[peggy]

Hi need for this P5 qtn.


Hansel and Gretel had 720 sweets. Hansel gave 1/7 of his sweets to Gretel . In return Gretel gave 1/6 of her sweets to hansel. In the end they had an equal numberbof sweets each. How many sweets did hansel have at first?

Thanks!

[Muffins]

Hi peggy!


Lemme try to help:

In the end, they had 720 ÷ 2 = 360

360 × 6 = 2160

2160 ÷ 5 = 432 (what Gretel had after Hansel gave her 1/7 of his sweets)

720 - 432 = 288

288 ÷ 6 = 48

48 × 7 = 336 → What Hansel had in the beginning

Hope that helped!

[rossypolly]

PLs help me with this question. Thks


The ratio of the number of Andy's sweets to the number of Randy's sweets was 4:1.After Andy bought another 13 sweets & Randy was given 7 more by his sister, the ratio of Andy's sweets to Randy's sweets became 3:1.

How many sweets did Andy have at first?