Q&A - PSLE Math

[anneshirleygilbert]

Can somebody please help with this question?


From Level 1 to Level 2, there were 2 flights of stairs of equal number of steps. For the first flight of stairs, Jerry walked up some steps and ran 13 steps, and took a total of 38 seconds.
Then, he got tired and for the second flight of stairs, he walked up some steps and ran 5 steps, taking 70 seconds this time. (Assume that the speed of walking and running for both flights of stairs remains constant.).
Hoe many minutes will Jerry take if he only walks up from Level 1 to Level 2? (Answer given is 3 minutes).

TIA

[tianzhu]

anneshirleygilbert:

Can somebody please help with this question?


From Level 1 to Level 2, there were 2 flights of stairs of equal number of steps. For the first flight of stairs, Jerry walked up some steps and ran 13 steps, and took a total of 38 seconds.
Then, he got tired and for the second flight of stairs, he walked up some steps and ran 5 steps, taking 70 seconds this time. (Assume that the speed of walking and running for both flights of stairs remains constant.).
Hoe many minutes will Jerry take if he only walks up from Level 1 to Level 2? (Answer given is 3 minutes).

TIA

Hi

Good Morning.

You may express in MD or use letters of alphabet.

For first flight
W + R13 --------38

For the second flight
W + R5 -------- 70

Difference in time between running and walking 8 steps --------- 32 (70-38)

Hence the difference between running and walking 1 step -------- 32/8 --------4

Now go back to the second flight, if you now walking instead of running 5 steps,you’ll add (5*4) --------20 s

W +W5 -------- 70 + 20 -------- 90

90*2 ------ 180

For both flights (walk), the time taken is 180 seconds or 3 minutes

Best wishes

[anneshirleygilbert]

Thank you very much, tianzhu. Wasn’t expecting anyone so early. Have a good day!

[small]

anneshirleygilbert:

Can somebody please help with this question?


From Level 1 to Level 2, there were 2 flights of stairs of equal number of steps. For the first flight of stairs, Jerry walked up some steps and ran 13 steps, and took a total of 38 seconds.
Then, he got tired and for the second flight of stairs, he walked up some steps and ran 5 steps, taking 70 seconds this time. (Assume that the speed of walking and running for both flights of stairs remains constant.).
Hoe many minutes will Jerry take if he only walks up from Level 1 to Level 2? (Answer given is 3 minutes).

TIA

I think Tianzhu posted this question before for us to try.

[superksmum]

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.

Hi MathIzzFun,

May i know how you get $51500000/33?
Thank you.

[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.