Q&A - PSLE Math

[MathIzzzFun]

superksmum:

MathIzzzFun:

[quote=\"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.

Hi MathIzzFun,

May i know how you get $51500000/33?
Thank you.[/quote]Hi

original price of both properties
= $800 000/1.1 + 1 000 000/ 1.2
= (960 000 + 1 100 000)/1.32
= 2 060 000/1.32
= 2 060 000/ (0.04 x 33)
= 51 500 000/33

cheers.

[Winx5015]

Hi MathIzzzFun,


Thanks for your solution

[ppspbubble]

There were some red pens and blue pens in a box. 30% of the pens were red. When 82 pens were added, the number of red pens increased by 20% while the number of blue pens increased by 50%. How many blue pens were there in the box in the end?

[ppspbubble]

65% of the members in the IT club were male. When 212 more members joined the club, the number of male members increased by 60% while the number of females= members increased by 60%. How many members were there in the end?

[MathIzzzFun]

ppspbubble:

There were some red pens and blue pens in a box. 30% of the pens were red. When 82 pens were added, the number of red pens increased by 20% while the number of blue pens increased by 50%. How many blue pens were there in the box in the end?

Hi

At first,
Red : Blue --> 30u : 70u -- total = 100u
in the end,
Red : Blue --> 30u x 1.2 : 70u x 1.5 = 36u : 105u -- total = 141u

Increase = 41u --> 82, 1u --> 2
In the end, blue pens --> 105 x 2 = 210

cheers.

[MathIzzzFun]

Winx5015:

Hi MathIzzzFun,


Thanks for your solution

u r welcome

cheers.

[2DMommy]

Please help me with these questions :


1) Eve, Francis and Gerald collected a total of 1007 empty plastic bottles for
a competition. After Eve gave 3/7 of her share to Francis and Francis gave 29 bottles to Gerald, the ratio of the number of bottles Eve collected to the number of bottles Gerald collected became 4 : 1. Given that Francis had 212 plastic bottles at first, how many plastic bottles did Francis have in the end ?

2) Jones had some gold and silver coins in his vault. If he took out 39 gold coins, the total number of coins will be 6 times of the number of gold coins. If he took out 30 silver coins, the number of silver coins will be twice of the number of gold coins. How many coins did Jones have in his vault?

Thank you !

[MathIzzzFun]

2DMommy:

Please help me with these questions :


1) Eve, Francis and Gerald collected a total of 1007 empty plastic bottles for
a competition. After Eve gave 3/7 of her share to Francis and Francis gave 29 bottles to Gerald, the ratio of the number of bottles Eve collected to the number of bottles Gerald collected became 4 : 1. Given that Francis had 212 plastic bottles at first, how many plastic bottles did Francis have in the end ?

Thank you !

Hi

At first,
Eve + Francis --> 1007 - 212 = 795
In the end,
Eve : Francis --> 4u : 1u -- total = 5u
So,
At first, Eve : Francis --> 7u : 1u - 29 -- total = 8u - 29
8u-29 = 795
1u--> 103

In the end, Francis --> 1007 - 5 x 103 = 492

cheers.

[MathIzzzFun]

2DMommy:

Please help me with these questions :


1) Eve, Francis and Gerald collected a total of 1007 empty plastic bottles for
a competition. After Eve gave 3/7 of her share to Francis and Francis gave 29 bottles to Gerald, the ratio of the number of bottles Eve collected to the number of bottles Gerald collected became 4 : 1. Given that Francis had 212 plastic bottles at first, how many plastic bottles did Francis have in the end ?

2) Jones had some gold and silver coins in his vault. If he took out 39 gold coins, the total number of coins will be 6 times of the number of gold coins. If he took out 30 silver coins, the number of silver coins will be twice of the number of gold coins. How many coins did Jones have in his vault?

Thank you !

Hi

If 30 silver coins taken out, Silver : Gold --> 10u : 5u
Total number of
Silver : Gold
--> 10u + 30 : 5u --- total = 15u + 30
--> 5 x (2u+6) : 5u

If 39 gold coins taken out, Silver : Gold --> 5:1 --> 5 x (2u+6) : 2u +6
After taking out 39 gold coins, gold coins left = 5u - 39
5u-39= 2u+6
1u--> 15
Total coins in vault = 15 x 15 + 30 = 255

cheers.

[small]

2DMommy:

Please help me with these questions :


1) Eve, Francis and Gerald collected a total of 1007 empty plastic bottles for
a competition. After Eve gave 3/7 of her share to Francis and Francis gave 29 bottles to Gerald, the ratio of the number of bottles Eve collected to the number of bottles Gerald collected became 4 : 1. Given that Francis had 212 plastic bottles at first, how many plastic bottles did Francis have in the end ?

Thank you !

Hi,

HTH..

For Francis, he had 212 bottles at first, after received 3 units from Eva and gave 29 bottles to Gerald thus:

At the end
Eve : Gerald : Francis ---- 4u : 1u : 183+3u

so at first
Eve : Gerald : Francis ---- 7u : 1u-29 : 212

Given that Eve, Francis and Gerald collected a total of 1007 empty plastic bottles.

7u + 1u-29 + 212 = 1007
8u + 183 = 1007
8u = 824
1u = 103

Francis had 183 +3u in the end

183 +3u ----- 183 + 3 x 103 = 492