Q&A - PSLE Math

[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.

[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.

[Jasmy]

Hi MathIzzzFun,


Thank you so much for ur reply. I have been trying to solve these qns this whole morning and afternoon :frustrated: but still couldn't get the ans. Wondering how my dd going to solve this type of qns given the time limit in exam.

[underthesea]

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.

Coffeecat,

Thank you so much. :thankyou:

[2cor41618]

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.

I got 7 2/9 hrs as the answer, doesn't look very correct, is it? :scratchhead:

[MathIzzzFun]

2cor41618:

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.

I got 7 2/9 hrs as the answer, doesn't look very correct, is it? :scratchhead:

Hi

it is not a nice number but your answer is correct..

cheers.

[kiasuaunt]

MathIzzzFun:

2cor41618:

[quote=\"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.

I got 7 2/9 hrs as the answer, doesn't look very correct, is it? :scratchhead:

Hi

it is not a nice number but your answer is correct..


cheers.[/quote]Can I hv the working pls? Thank you.

[Michaelia0816]

Yes of course

[speedmaths.012624com]

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.

Hi,

The cars took 5 - 3 = 2 hours to close up 760 - 400 = 360 km.
The cars took 2 hours to close up 360 km.
The cars will take another 400/360 x 2 = 2 2/9 hours to close up the last 400 km.

5 + 2 2/9 = 7 2/9 hours.

Hope this helps.

Cheers


speedmaths.com