Question

When Mr. X was asked how old he was, he said, “I will be Y years old in year Y2
, guess
how old I am”
. Which year Mr. X was born in?
a) 1936
b) 1980
c) 1986
d) 1995
e) 2025

Answer 1

Mr. X was born in: (b) 1980

Explanation

Mr. X said that “I will be $y$ years old in year $y^2$"

That means the year $y^2$ should be a squared number. In this century, the squared number year is only 2025.

Now, $y^2= 2025 \\ \\ y= \sqrt{2025}=45$

So, Mr. X will be 45 years old in the year 2025.

That means, he was born in the year: $2025 - 45 = 1980$