A fifth puzzle from the set!
\begin{align}3+4&=17\\2+5&=7\\3+1&=2\\2+1&=1\\4+2&=0\\3+6&=\,\,?\end{align}
Can you find the value of the question mark?
Puzzling Stack Exchange is a question and answer site for those who create, solve, and study puzzles. It only takes a minute to sign up.
Sign up to join this communityA fifth puzzle from the set!
\begin{align}3+4&=17\\2+5&=7\\3+1&=2\\2+1&=1\\4+2&=0\\3+6&=\,\,?\end{align}
Can you find the value of the question mark?
It's quite a bit higher than the rest, but I want to say the answer is
513
The formula being
AB - BA
All equations:
34 - 43 = 81 - 64 = 17 25 - 52 = 32 - 25 = 7 31 - 13 = 3 - 1 = 2 21 - 12 = 2 - 1 = 1 42 - 24 = 16 - 16 = 0 36 - 63 = 729 - 216 = 513
Here is a quick observation I made.
$$a+b:= \frac{a(a^2+b-1)}{2}-1$$
However,
This only works for the first two equations: $(a,b)=(3,4)$ and $(a,b)=(2,5)$
And
A quick glance at the answer above reveals that I am most likely not on the right track anyway...