Q&A - PSLE Math

[kiasuaunt]

Thank you,Tianzhu.

[sleepyqueen]

sleepyqueen:

Michaelia0816:

Need help with those following hard question, from practice paper!


1) 10 cooks working for 8 hours each, can prepare a meal for 160 people. How many cooks will be needed to prepare a meal for 220 people if they are required to prepare in 8 hours?

for this i get 14 cooks required. Not sure correct or wrong.

There is an update to your question to \" How many cooks will be needed to prepare a meal for 220 people if they are required to prepare in 5 hours?\"

Hence the answer should be 22.
10 cooks 80 hours to cook for 160 ppl
1 cooks took 160/80 = 2ppl per hour
220/2 = 110 hrs required
110/5 = 22 cooks required for 5 hrs of working each

[genevieve08]

Thank you MathIzzzFun for your help.


Can anyone help me with one more math Question?

Julian had 300 more cards than Faizal . Julian gave 3/5 of his cards to
Faizal . Faizal then gave 1/4 of the total number of what he had then
to Julian . In the end , Faizal had 300 more cards than Julian . How
many cards did Julian have at first.

:thankyou:

[tianzhu]

genevieve08:

Can anyone help me with one more math Question?

Julian had 300 more cards than Faizal . Julian gave 3/5 of his cards to
Faizal . Faizal then gave 1/4 of the total number of what he had then
to Julian . In the end , Faizal had 300 more cards than Julian . How
many cards did Julian have at first.

:thankyou:

Hi

This question has been discussed before.

Hope this helps.

Best wishes

http://farm6.staticflickr.com/5248/5301831898_a925296513_z.jpg\">

[underthesea]

Faizal and Gary ran in a race. When Gary had completed the race, Faizal had only run 5/8 of the distance. Gary’s speed was 75m/min faster than Faizal’s speed. Both of them did not change their speeds throughout the race.

What was Faizal’s speed in m/min?

This question is from the PSLE booklet. Can someone help. Thanks.

[Jasmy]

Hi, need help on this


There were 225 apples and 253 oranges in box A.
There were 260 apples and 212 oranges in box B.
Mr Chia moved some apples and oranges from box B to box A.
In the end, 40% of the fruits in box A and 70% of the fruits in box B were apples.
How many fruits did Mr Chia move from box B to box A?


Beaker A and Beaker B contain some water.
If 46.5ml of water is drained out from Beaker A, the volume of the water in Beaker A will be 60% that of the water in Beaker B.
If 35.2ml of water is drained out from Beaker B, the volume of the water in Beaker B will be 85% that of the water in Beaker A.
What is the total volume of water in Beaker A and Beaker B?

[CoffeeCat]

underthesea:

Faizal and Gary ran in a race. When Gary had completed the race, Faizal had only run 5/8 of the distance. Gary's speed was 75m/min faster than Faizal's speed. Both of them did not change their speeds throughout the race.

What was Faizal's speed in m/min?

This question is from the PSLE booklet. Can someone help. Thanks.

Hi,
Let's look at what you are given.
\"When Gary had completed the race, Faizal had only run 5/8 of the distance\"
This immediately gives you a comparison (a ratio) of their speeds!
Speed of Gary : Faizal = 8:5
Now you are ready to use the next pience of information ...
3 units of speed = 75m/min
Faizal ' speed = 5 units = (75/3)*5 = 125m/min.

[kiasuaunt]

Car A left Singapore for Penang. Car B left Penang for Singapore at the same time using the same route. 3 hrs after the two cars had set off, they were 760 km apart. 5 hrs after they had set off, the distance between the two cars was 400 km. How many hrs after setting off would the two cars meet?


Thanks.

[MathIzzzFun]

Jasmy:

Hi, need help on this


There were 225 apples and 253 oranges in box A.
There were 260 apples and 212 oranges in box B.
Mr Chia moved some apples and oranges from box B to box A.
In the end, 40% of the fruits in box A and 70% of the fruits in box B were apples.
How many fruits did Mr Chia move from box B to box A?

Hi

Total number of apples --> 225 + 260 = 485
Total number of oranges --> 253 + 212 = 465
Total number of apples & oranges = 950

After transfer,
Total number of apples & pears in Box A --> 10u
Total number of apples & pears in Box B --> 10p
10u+10p--> 950
1u+1p--> 95

4u+7p = 485 (apples)
so, 3p --> 485 - 4 x 95 = 105
1p = 35
1u = 60

Fruits moved to box A = 10 x 60 - 225 - 253 = 122

cheers.

[MathIzzzFun]

Jasmy:

Hi, need help on this


Beaker A and Beaker B contain some water.
If 46.5ml of water is drained out from Beaker A, the volume of the water in Beaker A will be 60% that of the water in Beaker B.
If 35.2ml of water is drained out from Beaker B, the volume of the water in Beaker B will be 85% that of the water in Beaker A.
What is the total volume of water in Beaker A and Beaker B?

Hi

at first,
(add 46.5 ml back to Beaker A) Beaker A : Beaker B --> 3u + 46.5 : 5u

If 35.2ml drained from Beaker B,
Beaker A : Beaker B
--> 3u + 46.5 : 5u - 35.2 = 100 : 85 = 20 : 17

equalize/cross-multiply:
51u + 790.5 = 100u - 704
1u --> 30.5
Volume of water in
Beaker A --> 3 x 30.5 + 46.5 = 138 ml
Beaker B --> 5 x 30.5 = 152.5 ml

cheers.