Q&A - PSLE Math

[jonaandr]

please help to solve the problem.


Mrs Hodge bought three times as many key chains as stuffed toys and spent $124 in total. She spent $64 more on the stuffed toys than the key chains. Given that a stuffed toy cost $8.40 more than a key chain, find the cost of a key chain.

Thanks a lot!

[tianzhu]

jonaandr:

please help to solve the problem.


Mrs Hodge bought three times as many key chains as stuffed toys and spent $124 in total. She spent $64 more on the stuffed toys than the key chains. Given that a stuffed toy cost $8.40 more than a key chain, find the cost of a key chain.

Thanks a lot!

Hi

A neat way is to use MD.Due to time constraints, I shall give you only some pointers.

Amount@stuffed toys ------- 94

Amount@key chains ------- 30

Draw 3 boxes to show number of key chains.

Draw 1 box to show number of stuffed toys.

Cost of 1 unit of key chains -------30/3 ------- 10

Cost of 1 unit of key chains -------94

94 – 10 ------ 84

This extra $84 is due to the number of stuffed toys costing $8.40 more than a key chain.

Number of stuffed toys ------ 84/8.4 ------- 10

Number of key chains ------- 30

Cost per key chain ------- 30/30 ------- 1

Best wishes

[cimman]

brastilava:

Hi, please help in these 2 questions:


2) I am a 2-digit number. I am a multiple of 4. When I am divided by 9, there will be a remainder of 6. When I am divided by 7, there will be a remainder of 5. Who am I?

some terminology foundation first:
http://i45.tinypic.com/21oas2d.png\">

coming up with the equation:
http://i49.tinypic.com/dev04m.png\">

plugging in the numbers:
http://i48.tinypic.com/1zlsm88.png\">

[rajamalar]

hi thank you for your method it is fambous

[cimman]

rajamalar:

hi thank you for your method it is fambous

you're welcome.

[imacsg]

At 9am Jerome left P Town for Y Town which was 540 km away. 2 hours later, Michael left P town for Y Town. He travelled at an average speed of 40 km/h faster than Jerome and overtook him at 3 pm.

a) What was Jerome’s average speed?
b) How far was Jerome from Y town when Michael reached his destination?

Can anyone help the above question? Thanks.

[MathIzzzFun]

imacsg:

At 9am Jerome left P Town for Y Town which was 540 km away. 2 hours later, Michael left P town for Y Town. He travelled at an average speed of 40 km/h faster than Jerome and overtook him at 3 pm.

a) What was Jerome's average speed?
b) How far was Jerome from Y town when Michael reached his destination?

Can anyone help the above question? Thanks.

Michael left Town P at 11 am and overtook Jerome at 3 pm ie 4 h later
40 km/h x 4h = 160 km --> Michael travelled 160km more than Jerome in 4h -- this is the \"catch up\" distance which is the distance travelled by Jerome from 9am to 11 am (2h)
Jerome's speed = 160 km/2 h = 80 km/h

alternatively, we can also use time ratio/speed ratio
When they meet,
time taken by Michael --> 11 am to 3 pm --> 4h
time taken by Jerome --> 9 am to 3pm --> 6h
Speed ratio of Michael : Jerome = 6 : 4 --> 3u : 2u
1u --> 40km/h, Jerome's speed --> 2 x 40 km/h = 80 km/h

with this, I think you can work out part (b)


cheers.

[AJH]

tianzhu:

AJH:

Hi - how did u get 480? I got 460. Thank u.

Hi

This question is crafted in such a way that it’s neat to use MD.

You may also use Units and Parts or letters of the alphabet to show the variables.

What you are seeing now is already the MD.The boxes are labelled with units and parts to enable students using the UP to see better.

The number “480” refers to the number of girls.

Best wishes

:thankyou: for your help. But isn't 30% of students in the parade ground and 70% of students at the indoor sports hall = 180 + 280 = 460?

[AJH]

tianzhu:

AJH:

Hi - nd help with this question:


Mr Lee packed some oranges into big boxes and apples into small boxes. Each big box contained 50 oranges and each small box contained 30 apples. After packing, there were 12 more big boxes than small boxes. Given that there were 1240 fewer apples than oranges, how many oranges were there? ( ans: 2200 )

Thank you.

Hi

You may use MD or work with units.

Draw three boxes (stacked up) to show the number of apples.

12*50 ------ 600

Draw five boxes to show the number of oranges. To make the MD look neater, divide 600/5 to give 120, add a bar showing 120 to each of the box.

5 boxes + 600 ------- 3 boxes + 1240

2 boxes ------- 640

1box ------ 320

Number of apples ------- 2200

Best wishes

:thankyou: I understand now.

[imacsg]

Hi MathIzzzFun,

Thanks for your prompt reply.

I know how to do part B. Thanks alot.