KiasuParents - Parenting in Singapore

S-H wrote: ↑

Mon Oct 15, 2018 3:09 pm

Hi can somebody help me with this qtn, thank you!
The volume of a block is 0.03 cubic metres, correct to the nearest 0.01 cubic metres. Find the greatest possible height of the block in metres.

The question is incomplete.. you did not mention if shape of the block.. the only way to solve it is if it is a cube. Else.. the greatest possible height will be infinity...

This question is testing your understanding of upper bound.. it came out only once in the O level..(which killed many students).. other than that.. it has not come out yet..

How to approach..
Volume is 0.03.... ( correct to 0.01).. to find greatest possible height.. you need to know greatest possible volume... in this case the greatest possible volume is 0.03499999999999999999,,,, the upper bound is 0.035.
Take cube root.. and you will get greatest height possible if it is a cube.


If you do not understand why 0.0349999999999..... is 0,035... you need to understand why 0.9 recurring is equal to 1. Google or PM me..

have fun.

0.034 rounded off to the nearest 0.01 is 0.03
0.025 rounded off to the nearest 0.01 is also 0.03

So anything between 0.025 and 0.034 rounded off to the nearest 0.01 is 0.03.

Hope that helps.

The Math Note wrote: ↑

Thu Mar 28, 2019 11:05 am

0.034 rounded off to the nearest 0.01 is 0.03
0.025 rounded off to the nearest 0.01 is also 0.03

So anything between 0.025 and 0.034 rounded off to the nearest 0.01 is 0.03.

Hope that helps.

Sorry, unfortunately, your answer is wrong. I am a math teacher and am aware of the confusion this question causes to people not familiar with bounds.

The cambridge solution to a similar question in the o level is same as mine. Unfortunately, only teachers have access to the report.

Usually, if the question says a dimension is rounded to 0.01, the upper and lower bounds are found by taking that given dimension +/- 0.01/2 = 0.005.

So, in this case, they are 0.03 + 0.005 = 0.035 and 0.03 - 0.005 = 0.025

Hope this helps.

Sarah, you are right... but the reason why you take is because of
0.034999999999999 recurring is 0.035
This is the concept that o level is testing...
If not students will not understand because 0.035 rounded off to 0.01 is 0.04 ....

Hi,
I need E math tutor for my DD. Anyone can recommend? We are staying in the West. Prefer do home tuition. My DD is now Sec 4 and struggling. TIA

Hi,
I need E math tutor for my DD. Anyone can recommend? We are staying in the West. Prefer do home tuition. My DD is now Sec 4 and struggling. TIA

Hi Candy08, I've private message you on my son's tutor. Graduated O level last yr with the tutor's help:) Not sure if he travels to West but you can text him to ask .
If you didn't receive my PM, you can email me for his contacts : [email protected]

Cheers!

Thanks a lot!

Candy08 wrote: ↑

Fri Apr 12, 2019 5:04 pm

Hi,
I need E math tutor for my DD. Anyone can recommend? We are staying in the West. Prefer do home tuition. My DD is now Sec 4 and struggling. TIA

Hi Candy08, you may consider my dd1 ex tutor Miss Goh. She happens to be a home tutor in the West as well. She is a very experienced tutor who knows her stuff well and my dd1 was very motivated to study when under guidance and did consistently well. If you are keen, you may contact hef at 93989072. All the best!