Is there a way to solve this using models

Sreekanth Babu : Ratio is no different from a model for such questions, but it saves your child the need to draw many boxes.

Sreekanth Babu : I hope the model drawn helps your child. :)

Thank you the clear explanation, Caleb Tey!

The method that I will suggest requires the student to visualise the below. Given the mass of 5 identical big balls is equal to the mass of 7 identical small balls. Each big ball is 2.84 kg heavier. Imagine removing 2.84 kg from each of the 5 big balls, and convert the removed material into 2 small balls. So what is the mass of the small ball? Suggested solution: 2.84 times 5 divided by 2 = 7.1 kg (ans) Total mass of 5 big balls and 7 small balls = total mass of 14 small balls = 7.1 kg times 14 = 99.4 kg (ans)

can you show that as a bar method please?

Paul, I hope this helps.

ok thanks

ok ^ - ^

250 degrees

The exterior angle 70 degrees.

Answer shuld be 250 degrees - 360 minus 110

lol, the first two answers are what the dispute is all about! lol

Ban Har Yeap and Yueh Mei what are your thoughts?

Kho Tek Hong would be good to know your thoughts too please.

In mathematics, the exterior angle is with respect to a straight line, ie 180 degrees. Hence the sum of an exterior angle and its corresponding interior angle is 180 degrees.

The reflex angle at B, however, is 250 degrees

The company in question are adamant that the answer is 250 degrees.

https://www.mathsisfun.com/geometry/exterior-angles.html

What they are saying is that IF the line was extended then it would have been 70! Which in my opinion is a google search answer.

There is often confusion when it comes to differentiating an exterior angle from a reflex angle.

It is 70 degrees. Please remember the theorem of exterior angle of a triangle and that of the sum of exterior angles of a polygon.

Thank you all for your responses so far. Just needed reassuring that I wasn't reading it wrong or misunderstanding the question.

Happy to contribute my two cents'worth, Regards

I learnt something new today. Thank you Xavier.

Many thanks, Yeo See Yeong. A place like this gives all of us the opportunities to learn something new everyday. Cheers.

wow..... so much info in in the picture, when only 1 angle is of use....? 😱

Zhong Shu Hao there are other parts of the question like finding the area of the shaded part.

(a) Please check if this is a possible diagram. (b) How is knowing exterior angle useful in this context? Does a land surveyor need to know exterior angle? Context should be meaningful (c) The easy bit is the answer to the question: 70 degrees. It is how interior angle and exterior angle of polygons are defined. Secondary students have been learning that sum of exterior angles in any polygon is 360 degrees. Mohi Uddin Ahmed

totally agreed with Ban Har Yeap

the 6cm topup, I believe I can skip that step. Need to establish the height on the 19,200. The 19200 was used to fill up a surface area of 20x10 and 30x20 so surface area = 200 + 600 = 800 hence, 19200 / 800 = 24cm Height was 24cm before final topup Final top up was 6 cm. So total higher = 6+24 = 30cm

Sorry guys for the late reply. But that not the answer

Hello there, Jason. Would you be so kind as to let us know the given answer?

U almost there dont give up! Add base areas 800 and divide vol 19200 by 800 to get 24 then 24 plus 6 is 30.

I think Jason got 30cm too. But may think it is wrong since it is different from the given answer?

I haven't got the answer from the teacher. But she hinted that we have to use the ratio of

the base area

To find the volume. I don't understand why they need to give such a difficult question to student

Just manage to arrange a meetup with the teacher today . Will update on what is the answer.

Many thanks, Jason.

Just an update. The answer all of us gotten is correct. However the teacher said its a fluke cause we didn't use the ratio of the base area to come out with the answer. I am speechless when the teacher said that.

I hear ya.

what happen to 12ooml of water into tank A ?