We know that Donald Trump is the oldest president of America. He is now 73 years old. With age, the function of the human brain decreases. This is called cerebral atropy.
When a person reaches the age of 75, his brain function decreases by 15% compared to what when he was 25 years old.
Source: Wikipedia
This is the formula for calculating IQ.
Mental Age / Chronological age multiplied by 100 = IQAs Donald Trump's chronological age increases, so does his mental age decreasing accordingly.
Now we will calculate Trump's IQ...
Chronological age= 73
Mental Age= 19
IQ=(19/73)multiplied by 100
=26%
And that's my vote.