Thks 😊

I have a problem with this question too.

After comparison, guess n check still the best method for this q

I used algebra to solve this...

$10×4=$40 $345-$40=$305 (now the $10 notes is the same as $50 notes) Let's assume all the remaining 35-4=31 notes are $5 notes, so $5×31=$155 $305-$155=$150 $50+$10-$5-$5=$50 (when you decrease by two $5 notes, you add a $10 note and a $50 note so the Total amount of money will increase by $50) $150÷$50=3 3×2=6 31-6=25

I also feel that guess and check is the easier method here. Most students will have difficulty understanding the assumption method. Anyone has a better way to solve this?

Same here, I'll also use guess and check method to solve.

Guess n check is better cos this consists of 3 denominations.

If it is 2 then assumption is better.

35*$5=$175 $345-$175=$170 $5*4=$20 $170-$$20=$150 $150/$50=3 3 $50; 7 $10; 25 $5

Hmm.. The two answers are different?

Irene Ong's answer ✔️

The question is flawed. The area of the triangle should be 46.77cm^2, not 45cm^2. I just realised this is a Pri Sch question. You'll know why in future when you learn Circular Measure.

This question that mavis post is from last yr paper for one of the top sch. Saw a few sch set this question with diff figures number for their sch exam.

In summary, based on the "wrong" question of 45, yah, pls use Irene Ong answer. But I promise you the true answer is what I've just given you ☺ But I must admit I used a sec school method to solve, coz I thought I was in another group. My fault ☺

In Math, once sufficient conditions are known, certain things become determinate. So for this question, it's not up to individual schools to claim the area is 45, 46, 47, etc... no matter how "top" the school is. Just my two-cent worth opinion ☺

I actually got this working from here when I did this question for my kid before his mid year exam. If will be more clearer If you see this link http://geniebookapp.com/public_question/31176a/635fe0435cbfbd3cf4b71ba5e6451146fab5a838

Fyi, this website isn't entirely correct either (though for Pri Sch, I definitely agree with your solving method) When the diameter is 14 cm, the area of the triangle isn't 60cm^2 either. It is 63.65cm^2 (Area=0.5x7x7xsin120 x 3 = 63.65cm^2)

Irene Ong, for Mavis Low problem, if you had started with 46.77, our answers would have been the same... ☺

Ok got it, thanks!