Question

If PEN is written as '+X' and ENT is written as 'X-' in a certain code, how is TEN written in the same code?

Answer 1

This one too is only a game of observation.
The first think to notice is that PEN has three characters while + X has only two.so two characters of PEN have been replaced by a single character.The same pattern can be seen in the case of ENT.So one must look for something common in the two of them PEN and ENT.
PEN=+X
ENT=+X
The common feature in both the above are 'EN' and X. So obviously
P=+,EN=X and T= -.
TEN=-X.