2
$\begingroup$

Using operators plus (+), minus (-), multiplication (x) and division (/), power function/exponentiation (^) and as many brackets as you want, can you find

A formula which uses 2,3,5,7 to make 93?

$\endgroup$
  • $\begingroup$ I would be able to do it with two $2$s; i.e., $5^3-2^{7-2}=93$. (The same goes for two $5$s since $7-2=5$.) Also, including concatenation, I could create another formula with two $2$s: $57+(2\times 3)^2$, and another: $75+(2\times 3^2)$, and yet another: $23 + (2\times 5\times 7)$, and even another: $73 + (5\times 2^2)$. $\endgroup$ – Feeds Jul 31 '18 at 11:09
  • $\begingroup$ I finally was able to make one, but it uses a $0$. $$7^3-250=93.$$ That's the best I can do without using @Glorfindel 's answer. $\endgroup$ – Feeds Jul 31 '18 at 11:19
  • $\begingroup$ @user477343 Glorfindel's answer is unique :) $\endgroup$ – Oray Jul 31 '18 at 11:20
  • $\begingroup$ Indeed... but is there a way to prove that his answer is the only one that satisfies the puzzle? $\endgroup$ – Feeds Jul 31 '18 at 11:20
  • $\begingroup$ @user477343 yes coding. $\endgroup$ – Oray Jul 31 '18 at 11:21
3
$\begingroup$

Are we allowed to

concatenate numbers?

If so,

$2^7 - 35 = 93$ works.

$\endgroup$
  • $\begingroup$ no restriction for concatenation is defined, so you can :) good finding! $\endgroup$ – Oray Jul 30 '18 at 8:36
  • $\begingroup$ Concatenation strictly speaking is an operation, and isn’t listed as one. $\endgroup$ – Neil W Aug 2 '18 at 12:38
  • $\begingroup$ @NeilW sure, hence my question if it was allowed. I've tried to brute force a solution without concatenation later, but that wasn't successful. $\endgroup$ – Glorfindel Aug 2 '18 at 13:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.