To attempt a logical question in math, the mind has to be concentrated and flexible.<quoted text>
22 is correct. My reasoning stopped short.
Be incisive as well as comprehensive in your analysis and don't stop short after a cursory attempt.
Re-evaluate the answer by closely scrutinizing the wordings of the question and your own working steps and only after exhausting all possibilities then stop.
If still you make a mistake, then, well, it means that your intellectual capacities are limited to the incorrect answer you gave or maybe that you're not focused enough.
But, with you, both the answers (20 and 21) given to the same question on the sweets over a gap of many months indicate that your mental faculties are as good as the (incorrect) answers that you provided.
As a student, I could sit for hours at a stretch working on trick problems without a break and without so much as looking up.
I thought CEOs or ex-CEOs were smarter and had deep number crunching skills unless the person was/is a CEO of a porn company where stats pertaining to bamboo size matters.
No big deal.
Kisses and hugs,
(twink wink twink wink)