Q&A - PSLE Math

[Denise]

Denzel, Eugene and Farhan bought a packet of marbles. Denzel received 145 marbles.Farhan received 30% less marbles than Eugene. Later,Denzel gave 68 marbles to Eugene and Farhan to share. After that, Farhan still had 30% fewer marbles than Eugene. The number of marbles Eugene had increased by 25%. How many marbles were there in the packet at first?

[tianzhu]

Denise:

Denzel, Eugene and Farhan bought a packet of marbles. Denzel received 145 marbles.Farhan received 30% less marbles than Eugene. Later,Denzel gave 68 marbles to Eugene and Farhan to share. After that, Farhan still had 30% fewer marbles than Eugene. The number of marbles Eugene had increased by 25%. How many marbles were there in the packet at first?

Hi

You may use MD or work with units.

To avoid working with decimals, use equivalent ratios.

Denzel received 145 marbles

Eugene ------- 40 units
Farhan ------- 28 units

Denzel gave 68 marbles to Eugene and Farhan to share.

Eugene ------- 50 units
Farhan ------- 35 units.

(35+50) – (40+28) ------- 17

17 units ------- 68
1 unit ------- 4

68 units ------- 272

272+145 ------ 417

Best wishes

[Denise]

Thanks. That was fast.

[Winx5015]

Hi, here are some heuristic questions that need help.


(1). Jane saves 25% of her salary each month. Her salary increased by 30% in July. If her savings from July till the end of the year amounted to $3120, how much was her monthly salary before the increment?

(2). Jerry and Mosses each had a certain number of stamps. At first, Mosses had 200 stamps more than Jerry. When Mosses gave away 1/6 of his stamps to Jerry, he had 30 fewer stamps than Jerry. What was the ratio of the number of stamps Jerry had to the number of stamps Jerry had to the number of stamps Mosses had at first?

(3). If Tom sells the watch at a discount of 15% of the marked price, he will make a profit of $8. If he sells it at a discount of 30% of the marked price, he will suffer a loss of $4. Find the cost price of the watch.

Thanks.

[MathIzzzFun]

Winx5015:

Hi, here are some heuristic questions that need help.


(1). Jane saves 25% of her salary each month. Her salary increased by 30% in July. If her savings from July till the end of the year amounted to $3120, how much was her monthly salary before the increment?

(2). Jerry and Mosses each had a certain number of stamps. At first, Mosses had 200 stamps more than Jerry. When Mosses gave away 1/6 of his stamps to Jerry, he had 30 fewer stamps than Jerry. What was the ratio of the number of stamps Jerry had to the number of stamps Jerry had to the number of stamps Mosses had at first?

(3). If Tom sells the watch at a discount of 15% of the marked price, he will make a profit of $8. If he sells it at a discount of 30% of the marked price, he will suffer a loss of $4. Find the cost price of the watch.

Thanks.

Hi

Q1.... Savings per month from Jul - Dec= $3120 / 6 = $520
Savings per month = Salary x 25% x 130% = 0.325 x Salary
so, salary = 520 / 0.325 = $1600

Q2.
After 1/6 of stamps to Jerry,
Mosses's stamps -> 5 units
Jerry's stamps --> 5 units + 30

At first,
Mosses's stamps -> 6 units
Jerry's stamps --> 4 units + 30
so,
6 units = 4 units + 30 + 200
2 units --> 230
Jerry's stamps : Mosses's stamps = 490 : 690 = 49 : 69

Q3.
15% (= 30% - 15%) of marked price = $4 + $8 = $12, you should be able to work out the rest from here..

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cheers.

[superksmum]

Hi, help needed again.


Mr Brown made two real estates sales. The first property was transacted at $800,000, and he gained 10% from it. The second property was transacted at $1,000,000, and the gain was 20%. What was his average gain in percentage for the two properties?

Thanks you

[MathIzzzFun]

superksmum:

Hi, help needed again.


Mr Brown made two real estates sales. The first property was transacted at $800,000, and he gained 10% from it. The second property was transacted at $1,000,000, and the gain was 20%. What was his average gain in percentage for the two properties?

Thanks you

Hi

Original price of 1st property = $800 000/1.1
Original price of 2nd property = $ 1000 000/ 1.2
Total original price = $51500000/33
Total transacted price = $ 1800000
$1800000/($51500000/33) x 100% = 115.34% (to 2 decimal places)
So, average percentage gain = 15.34%

cheers.

[cycjca]

Hi

need help super-desperately:

A min ago, 40% of the people in the theatre were adults, 210 more people entered the theatre. As a result, the number of adults increased by 100% and the number of children increased by 50%. How many people are there in the theatre now?

Thanks in advance.

[small]

cycjca:

Hi

need help super-desperately:

A min ago, 40% of the people in the theatre were adults, 210 more people entered the theatre. As a result, the number of adults increased by 100% and the number of children increased by 50%. How many people are there in the theatre now?

Thanks in advance.

Hi,

HTH...

Before
The ratio of adult to children ----- 4 : 6 (total 10 units)

After
adults increased by 100% and the number of children increased by 50%.
thus the ratio of adult to children nou ----- 8 : 9 (total 17 units)


Thus means after 210 more people entered the theatre, there are increasing of 7 units

7 units ----- 210
1 unit ----- 30

People in the theatre now ------ 17 units

17 units --- 17 x 30 = 510 people.

[cycjca]

Thank you so much! Now we can try to solve the remaining paper…Thanks again!