Q&A - PSLE Math

[Dazzle]

Tianzhu and ksmama,

Thanks for solving the handshake problem.

[Dazzle]

ksmama:

Hi, tianzhu, tks for reminder that can use units in equal total concept.

Soln in units method:
Case 1 mrs Li. M:W
3:1. (total 4 units)

Case2 mr Li. M:W
4:1. (total 5 units)

Since we knw total no of people shd b d same, convert the total units to the same using LCM of 4 n 5

So case 1 bcom. M:W
15:5 (prev no x 5)

Case 2. M:W
16:4 (previous no x 4)

Therefore no of men=16; women=5

Just have a closer look, shouldn't Case 1 should be Mr Li and Case 2 is Mrs Li ?

[match3frog]

Regarding the handshake problem - I’m just wondering, what if the student thinks that Mr & Mrs Li don’t shake hands with each other because they already know each other. Wouldn’t the answer be different?

[MathIzzzFun]

match3frog:

Regarding the handshake problem - I'm just wondering, what if the student thinks that Mr & Mrs Li don't shake hands with each other because they already know each other. Wouldn't the answer be different?

Hi

the answer will be different, but the question says : \"A group of people met at a party. Each person shook hands with everyone else.\" so regardless of whether anyone knows someone else at the party, it will have to be taken that each will shake hands with everyone else.

cheers.

[match3frog]

Hi mathizzzfun, good morning and thanks for your reply. I have to read the questions carefully


Hi ksmama, thanks for posting the solutions using units method!

[2DMommy]

Need help with these 2 questions :


1)Denise and Jenette went shopping with a total of $380. After buying some items each, the amount Denise has left is 4 times the amount she spent and the amount Jeanette has left is thrice the amount she spent. The two friends had a total of $296 left. How much did Denise have at first ?

2)Nelson had 40% less money than Kai Lin. Maria had 20% more than the amount Nelson had. Maria spent 50% of her money on clothes and found that the amount she had left was $300 less than Nelson's. How much did Kai Lin have ?

Thank you in advance

[tianzhu]

2DMommy:

Need help with these 2 questions :


1)Denise and Jenette went shopping with a total of $380. After buying some items each, the amount Denise has left is 4 times the amount she spent and the amount Jeanette has left is thrice the amount she spent. The two friends had a total of $296 left. How much did Denise have at first ?

2)Nelson had 40% less money than Kai Lin. Maria had 20% more than the amount Nelson had. Maria spent 50% of her money on clothes and found that the amount she had left was $300 less than Nelson's. How much did Kai Lin have ?

Thank you in advance

Hi

Due to time constraints, I’ll be providing some pointers instead of MD.

For Q1, there are two variables. Using simultaneous concepts, you may solve it pictorially, using units and parts or simply using letters of the alphabet. There are some examples if you refer to the earlier posts.

For Denise
Left ----- D
Spent ----- DDDD

For Jenette
Left ----- JJJ
Spent ----- J

DDDD + JJJ ------ 296
D + J ----- 84
D + (3*84) ------ 296

D ----- 44

Hence, Denise had (44*5) or 220 at first.

For Q2, you may choose to work with percentages or units.

Kai Lin ----- 100%
Nelson ----- 60%
Maria ----- 72%

Maris spent 36% (half or 50%)

60 – 36 ----- 24

24% ----- 300
4% ------ 50

100% ------ 50*25 ------ 1250 (Kai Lin)

Best wishes

[Winx5015]

Hi, a very Happy New Year to all members of Kiasu Parents. :celebrat


Following is a question on algebra.

Jane has 4c marbles. Ivan has 1/3 the marbles Jane has. Gerald has 1/4 the marbles Ivan has. how many marbles does gerald have in terms of c?

Thanks :thankyou:

[MathIzzzFun]

Winx5015:

Hi, a very Happy New Year to all members of Kiasu Parents. :celebrat


Following is a question on algebra.

Jane has 4c marbles. Ivan has 1/3 the marbles Jane has. Gerald has 1/4 the marbles Ivan has. how many marbles does gerald have in terms of c?

Thanks :thankyou:

Hi

Gerald --> 1/4 of Ivan --> 1/4 of (1/3 of Jane) --> 1/4 x 1/3 x 4c = 1/3 c

cheers.

[Winx5015]

Hi mathIzzzFun,


Thanks for your help :thankyou: