Q&A - PSLE Math

[tianzhu]

Hi Belle2011


Hope this helps.

To begin with, I am wondering if this question is within the PSLE syllabus.
I think I saw such question under direct/Inverse proportion in secondary two textbooks.

There are three variables in this question, namely the number of men, the number of houses and the number of days. The key to unlock this question is to keep one variable constant at any one time.

I have included more steps to enable better understanding; as usual,you may consolidate some of the steps once you are able to grasp the concepts better.

Best wishes

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[Hifive]

Hello everyone


HAPPY NEW YEAR!

I’ve a question:

Peter, Queenie, Regina and Sally saved $1030. The ratio of Peter’s money to Queenie’s money was 1 : 2. Peter took 2/5 of Regina’s money. He then gave $95 from the amount taken from Regina to Sally. Finally, the 3 girls had the same amount of money.

a) How much did Regina have at first ?
b) How much did Sally have in the end?

Appreciate your advice.

[Dharma]

Hifive:

Hello everyone


HAPPY NEW YEAR!

I've a question:

Peter, Queenie, Regina and Sally saved $1030. The ratio of Peter's money to Queenie's money was 1 : 2. Peter took 2/5 of Regina's money. He then gave $95 from the amount taken from Regina to Sally. Finally, the 3 girls had the same amount of money.

a) How much did Regina have at first ?
b) How much did Sally have in the end?

Appreciate your advice.

At first, their share
Peter : 3u
Queenie : 6u
Regina : 6u + 4u = 10u
Sally : 6u - $95

25u - $95 = $1030
25u = $1125
1u = $45

a) Amt Regina had at first = 10u = $450
b) Amt Sally had in the end = 6u = $270

[Hifive]

Hi Dharma


Good morning! Thanks for the solution.

Can you pls advise on how do you derive that Peter : 3u and Queenie : 6u?

Thanks!

[Dharma]

Hifive:

Hi Dharma


Good morning! Thanks for the solution.

Can you pls advise on how do you derive that Peter : 3u and Queenie : 6u?

Thanks!

The final condition is :

The 3 girls had the same amount of money( I assumed 6u for each of the 3 girls).
Notice that Queenie's money did not change at all. So, Queenie had 6u at the beginning too.
Since the qn tells us that ratio of money Peter to Queenie at first is 1:2.
Therefore, Peter must have had 3u at first.

[Lynn2]

May I know anyone here can share where can I find very challenging questions for Circles?thanks


Rgds
Lynn

[Belle2011]

Dear everybody,

Happy New Year to you.

Here is another question from a worksheet given by a teacher from Just Education.

Karen is about as many days as her mother is in weeks and Karen is as months as her grandpa is in years. Karen, her mother and her grandpa are 160 years old altogether. How old is her grandpa?
(model answer: 96)

My problem is I dont really understand some parts in this question and thus unable to solve.

Thanks.

Cheers,
Belle.

[Dharma]

Belle2011:

Dear everybody,

Happy New Year to you.

Here is another question from a worksheet given by a teacher from Just Education.

Karen is about as many days as her mother is in weeks and Karen is as months as her grandpa is in years. Karen, her mother and her grandpa are 160 years old altogether. How old is her grandpa?
(model answer: 96)

My problem is I dont really understand some parts in this question and thus unable to solve.

Thanks.

Cheers,
Belle.

Karen : Mother = a days : a weeks = a/7 weeks : a weeks = 1 : 7
Karen : Grandpa = b months : b years = b/12 years : b years = 1 : 12

Karen : Mother : Grandpa : 1 : 7 : 12
1u + 7u + 12u = 160
20u = 160
1u = 8

Grandpa's age = 12u = 12 x 8 = 96 years old

[Belle2011]

Dharma:

Belle2011:

Dear everybody,

Happy New Year to you.

Here is another question from a worksheet given by a teacher from Just Education.

Karen is about as many days as her mother is in weeks and Karen is as months as her grandpa is in years. Karen, her mother and her grandpa are 160 years old altogether. How old is her grandpa?
(model answer: 96)

My problem is I dont really understand some parts in this question and thus unable to solve.

Thanks.

Cheers,
Belle.

Karen : Mother = a days : a weeks = a/7 weeks : a weeks = 1 : 7
Karen : Grandpa = b months : b years = b/12 years : b years = 1 : 12

Karen : Mother : Grandpa : 1 : 7 : 12
1u + 7u + 12u = 160
20u = 160
1u = 8

Grandpa's age = 12u = 12 x 8 = 96 years old

Dear Dharma,
Thanks very much for your prompt reply.

May I ask:
why consider weeks for Karen: Mother?
why consider years for Karen: Grandpa?
Also,
when you combine the 3 persons ie Karen: Mother: Grandpa, can we simply lump the ratios since Karen: Mother is originally in weeks and Karen: Grandpa is originally in years, if you know what I mean?
Thanking you in advance.

Cheers,
Belle.

[Hifive]

Dharma:

The final condition is :

The 3 girls had the same amount of money( I assumed 6u for each of the 3 girls).
Notice that Queenie's money did not change at all. So, Queenie had 6u at the beginning too.
Since the qn tells us that ratio of money Peter to Queenie at first is 1:2.
Therefore, Peter must have had 3u at first.

Hi Dharma

Thanks. I can understand now.