P and Q are similar in respect to property x.
P has been observed to have further property y.
Therefore, Q has property y also.
In my example I assumed limited supply of Motorola cellular phones. Meaning, Motorola phones(P) and Bitcoin(Q) are similar in respect to limited supply(x). Then I made the second premise: limited supply of Motorola phones
Even your P and Q statement would be considered really poor deductive reasoning.
Just because YOU label that something is similar does not make it so. ... For your deductive proof to work, Q would need to be a subset of P. Here are some examples of useful statements:
Elephants have cells in their bodies and all cells have DNA. Therefore, elephants have DNA.
All noble gases are stable. Helium is a noble gas, so helium is stable.
Here are examples of poor deductive reason (because poor assumptions are made, that is, Q is not necessarily a subset of P, or we have no proof of their properties matching up):
All swans are white. Jane is white. Therefore, Jane is a swan.
All farmers like burgers. Jethro likes chicken wings. Therefore, Jethro is not a farmer.
The above was taken from:
https://examples.yourdictionary.com/deductive-reasoning-examples.html