Q&A - PSLE Math

[numeric]

Please help!

In January, Joyce kept 80% of her salary of which she then gave 1/5 to her mother and saved the rest. The rest of her money was spent on food and clothing.In February,she gave her mother $150 more than the amount she had given her in January. The amount given to her mother was then equal to the amount she saved.She spent the same amount on food and clothing in January and February.

Question: What was the percentage increase in the amount Joyce gave to her mother in February?

Answer 1: 80%x1/5=16%; 80%x1/2=40%; 40%-16%=24%; 24%---->$150;

so gave mother in January : 16%---> $100;
gave mother in Feb: 40%----> $250
percentage increase: ($250-$100)/$100x100%=150%
Answer 2: In January: gave her mother 16%; In February, gave her mother 40%
so percentage increase: 40%-16%=24%

Please tell which answer is right? If Answer 1 is right, what kind of question expression may get Answer 2? If Answer 2 is right, what kind of question expression may get Answer 1?

"The amount given to her mother was then equal to the amount she saved.She spent the same amount on food and clothing in January and February."

[Polar_bear]

Please help!

In January, Joyce kept 80% of her salary of which she then gave 1/5 to her mother and saved the rest. The rest of her money was spent on food and clothing.In February,she gave her mother $150 more than the amount she had given her in January. The amount given to her mother was then equal to the amount she saved.She spent the same amount on food and clothing in January and February.

Question: What was the percentage increase in the amount Joyce gave to her mother in February?

Answer 1: 80%x1/5=16%; 80%x1/2=40%; 40%-16%=24%; 24%---->$150;

so gave mother in January : 16%---> $100;
gave mother in Feb: 40%----> $250
percentage increase: ($250-$100)/$100x100%=150%
Answer 2: In January: gave her mother 16%; In February, gave her mother 40%
so percentage increase: 40%-16%=24%

Please tell which answer is right? If Answer 1 is right, what kind of question expression may get Answer 2? If Answer 2 is right, what kind of question expression may get Answer 1?

"The amount given to her mother was then equal to the amount she saved.She spent the same amount on food and clothing in January and February."

Different opinion coming!
BTW, my son consulted his maths teacher and got a reply Answer 1 is correct.

So " percentage increase" and it's "reference" are really confused...

Thanks!

[Polar_bear]

Within this form, block with number 216 should be blank and to be disclosed. (image is answer key page)

Who can tell me how to get this(216) answer? My answer is simply "24"

[SOS mum]

Hi, ps help. Many tks and God Bless:)

The sum of two numbers is 106.8.
The first number has three decimal places.
The second number is 99 times the first number.
What is the first number.

[sushi88]

Within this form, block with number 216 should be blank and to be disclosed. (image is answer key page)

Who can tell me how to get this(216) answer? My answer is simply "24"

Are there any rules stated at the question part because you only post the answer?

One possibility of rules is that to get the numbers in the blocks above, it must always operate with the number in the lowest block, i.e. row 1.

So to get row 3, it is row 1 x row 2
But to get row 4, it has to be cube of row 1 instead of row 2 x row 3.
So row 4 result for 6 is 6x6x6 = 216.

So it is tricky if one does not read the rules given in the question because intuitively the pattern would be to use row 2 x row 3.

[sushi88]

Hi, ps help. Many tks and God Bless:)

The sum of two numbers is 106.8.
The first number has three decimal places.
The second number is 99 times the first number.
What is the first number.

Let the first number be u.
u + 99u =100u
100u -> 106.8
u -> 106.8/100 = 1.068
Hence the first number is 1.068

[SOS mum]

Hi, ps help. Many tks and God Bless:)

The sum of two numbers is 106.8.
The first number has three decimal places.
The second number is 99 times the first number.
What is the first number.

Let the first number be u.
u + 99u =100u
100u -> 106.8
u -> 106.8/100 = 1.068
Hence the first number is 1.068

Thank You very much..Sushi88

[SOS mum]

Sorry, I hv 2 more qns..TIA and GOD BLESS:)

1) Andy started driving from Town A To Town B at an average speed of 80km/h at 9am.
Benny started driving from Town B to Town A at an average speed of 100 km/h at 9.30am.
After 30 mins of driving, Benny covered 1/5 of his journey.
At what time would Andy and Benny meet each other?

2) Amy had some money.
If she bought a table and 5 identical chairs, she would spend all her money.
If she wanted to buy a table and an oven that cost $254 more than a chair, she would be short of $38.
How much money would Amy had left if she had bought the table?

[sushi88]

Sorry, I hv 2 more qns..TIA and GOD BLESS:)

1) Andy started driving from Town A To Town B at an average speed of 80km/h at 9am.
Benny started driving from Town B to Town A at an average speed of 100 km/h at 9.30am.
After 30 mins of driving, Benny covered 1/5 of his journey.
At what time would Andy and Benny meet each other?

Andy (9am) A-40km-(930am)---------------------->B

At 930 am, Andy travelled distance = 80 x 1/2 = 40km

Benny === A<-----------------250km---------------B (930am)

If 30 mins, Benny covered distance = 100 x 1/2 = 50km
If 1/5 journey is 50km, total distance = 50 x 5 = 250km

So at 930am for both, distance to cover = 250-40 = 210km
Starting from 930am, time to meet = 210/ (80+100) = 21/18 = 1 1/6 = 1 hour 10 mins

Hence time to meet = 9:30am + 1 hr 10 mins = 10:40am

[sushi88]

Sorry, I hv 2 more qns..TIA and GOD BLESS:)


2) Amy had some money.
If she bought a table and 5 identical chairs, she would spend all her money.
If she wanted to buy a table and an oven that cost $254 more than a chair, she would be short of $38.
How much money would Amy had left if she had bought the table?

----Table----U-U-U-U-U-
----Table----U-<-216--><--38--> where (216+38=254)

So 4u->216
u->54
Hence if Amy only bought table, money left =5U =5 x 54 = $270