Q&A - PSLE Math

[StaryNight]

lee tong fong:

Can you please help to solve another 2 more problem sum, thanks in advance


1)In July, Pauline spent 20% of a sum of money on tuition, 60% on food and saved the rest. In August, the sum of money was increased by 15%. She spent the same amount of money on tuition but increased her saving by 30%. She saved $390 in August.
a)How much money did she spend on tuition in July?
b)How much did she spend on food in August?

2) Azman had 25% more marbles than chongfu. Chongfu has 60% more marbles than Bala. During a game, Azman and Bala lost some marbles to Chongfu in the ratio 3:1 . In the end, Azman and Bala had 780 and 480 marble left respectively. How many marbles did Azamn have at first?

Hi lee tong fong,
this is the solution for the first question:
130/100 x 20 = 26 (% of money saved in August)
26%--> $390
1%--> $390/26 = $15
20%--> $15x20=300 (ans for part a)

(b)
100%--> 15x100=1500 (total sum of money in july)
1500-300-390=810 (ans for part b)

Hope this helps!

[lee tong fong]

Sure, your answer is correct and thank for your help.


Can you try to answer question 2. Thanks

[dazzlego]

Hi lee tong fong,


A:C = 125:100 = 5:4 (the one after the word than is always 100%)
C:B = 160:100 = 8:5
So A:B:C = 10:5:8 and A:B = 2:1

Rephrasing the questions to:
At first, A had 2 units and B has 1 unit. A lost 3 parts and B lost 1 part of their cards to C.
2u - 3p = 780
1u - 1p = 480

2u - 2p = 480 x 2 = 960
1p = 960 - 780 = 180
1u = 180 + 480 = 660
A: 2u = 660 x 2 = 1320

Cheers :celebrate:

lee tong fong:

Can you please help to solve another 2 more problem sum, thanks in advance

2) Azman had 25% more marbles than chongfu. Chongfu has 60% more marbles than Bala. During a game, Azman and Bala lost some marbles to Chongfu in the ratio 3:1 . In the end, Azman and Bala had 780 and 480 marble left respectively. How many marbles did Azamn have at first?

[lee tong fong]

Thanks for your answer and is it possible to use model instead of simultaneous equation to work out the solution.Thanks


2u - 3p = 780
1u - 1p = 480

2u - 2p = 480 x 2 = 960
1p = 960 - 780 = 180
1u = 180 + 480 = 660
A: 2u = 660 x 2 = 1320

[dazzlego]

lee tong fong:

Thanks for your answer and is it possible to use model instead of simultaneous equation to work out the solution.Thanks


2u - 3p = 780
1u - 1p = 480

2u - 2p = 480 x 2 = 960
1p = 960 - 780 = 180
1u = 180 + 480 = 660
A: 2u = 660 x 2 = 1320

Yes, it is possible. However since P6 students have already learned how to solve simultaneous equations, it's better to use it. This approach is less time consumed too.

Model:
2u = 3p + 780
1u = 1p + 480

http://i48.tinypic.com/21n2m49.jpg\">

1p = 480 + 480 - 780 = 180

[lee tong fong]

Got it ! Thanks for your time to draw the model.

[lee tong fong]

I have a new problem sum. Please help me to solve. Thanks in advance.


Joyce gave $480 of her monthly salary to her mother. She gave 30% of the reminder to her father. Althogether, she gave 58% of her monthly salary to her father and mother. She saved 20% of her monthly salary.
(a) What percentage of her monthly salary did she give to her father?
(b) How much did she save?

[Maths Hub]

lee tong fong:

I have a new problem sum. Please help me to solve. Thanks in advance.


Joyce gave $480 of her monthly salary to her mother. She gave 30% of the reminder to her father. Althogether, she gave 58% of her monthly salary to her father and mother. She saved 20% of her monthly salary.
(a) What percentage of her monthly salary did she give to her father?
(b) How much did she save?

First of all, we have to be clear that out of her salary, 20% is saved, 58% is given to parents, and 22% is for other purposes. The 22% and 20% of her salary will add up to the 70% of the remainder after giving to her mother.

Let her salary be 100 units. The amount that she saved is 20 units, the amount she gave her father and mother will be 58 units and 70% of the remainder will be 42 units.

70% of remainder-> 42 units
100% of remainder-> 42X10/7=60 units
Therefore 100 units - 60 units= 40 units is given to her mother and 58 units - 40 units = 18 units is given to her father.

a) 18 units/100 units = 18%
b) 40 units ->$480
1 unit -> $12
20 units ->$240

[MathIzzzFun]

lee tong fong:

I have a new problem sum. Please help me to solve. Thanks in advance.


Joyce gave $480 of her monthly salary to her mother. She gave 30% of the reminder to her father. Althogether, she gave 58% of her monthly salary to her father and mother. She saved 20% of her monthly salary.
(a) What percentage of her monthly salary did she give to her father?
(b) How much did she save?

..equal fraction approach ...

$480 + remainder = total salary

58% of salary given to father and mother
so,
$480 (mother) + 30% of remainder = 58% of salary
amount left:
70% of remainder = 42% of salary .... equal fraction
70/100 of remainder = 42/100 of salary
remainder = 6/10 of salary
$480 (mother) --> 4/10 of salary = 40% of salary
percentage of salary given to father = 58% - 40% = 18% of salary (a)

40% of salary --> $480
20% of salary --> $240 -- she saved $240 (b)

cheers.

[lee tong fong]

Thanks for your detail working solution. It is difficult to explain to kid the equal fraction concept


70% of remainder = 42% of salary … equal fraction
70/100 of remainder = 42/100 of salary
remainder = 6/10 of salary

Is there any simplify way to do so . Thanks