Profit for a Cake-Making Business

A long time ago, I was a maths teacher in a private secondary school in KK. Generally speaking, I'd say roughly about 60% of the human race is weak in maths. Of the remaining 40%, about 20% are of average ability, and just 20% (maybe even less than that) who're really good in the subject. Maths, to me, is a subject of "obeying rules". Those who'd excel in maths have the habit of checking the truth of the matter, and not just jump to conclusion. That is also the same reason why so many people are gullible and would fall prey to pranks and hoaxes spread through social media, simply because very few of them would check to verify whatever is it that's being spread.

I've had some major achievements as a maths teacher as I was able to help seemingly "stupid" students to pass the subject. Teaching is an art, and in order to teach well, the teacher must be able to bring himself down to the level of the student, and see the subject from the latter's point of view. But apart from seeing from the student's viewpoint, I also used plenty of examples from day-to-day calculations. Instead of using algebras and complex formulas, I'd use simple ordinary calculations. Somehow most people dread algebras and maths formulas. At the mere mention of them, their mind would shut down! But of course sometimes even simple ordinary calculations may not work too. I guess some people are just not mathematically-inclined!

Today, I have a somewhat complex calculation for a property valuation work, and having explained several times to my staff, she was still confused. In the end, I went back to my approach from all those years ago when I was a teacher. What I came up with was a cake-making business. It's like this:

The total cost for baking a cake is RM70. When the cake is done, you can sell it for RM100. Now the question is simple: How much profit in terms of percentage would you make from the business?

It's not a trick question. It's just a plain ordinary calculation that requires elementary mathematical ability. But you probably already know that she failed to answer the question. So what I did was to ask 2 other staff the same question, and they, too, failed to get the correct answer. Just out of curiosity, I asked my daughter the same question through WhatsApp, and to my great relief, she answered it correctly.

Now I'm posting the question here to see if my readers would like to give it a go? Like I said, this is not a trick question; I'm not here to trap the careless people like I sometimes do. If you're shy to respond here, you can also email your answer to me at: ckoh1965@yahoo.com.