A short statement can hide more than it seems. Here a careless reading is enough to arrive at the wrong answer; A careful reading, on the other hand, resolves it effortlessly.

The ages in a temporal mirror

Curious
Pure logic

Riddle statement

Someone says:

"Now I am 40 years old, and today I am 4 times the age you were when I was the age you are now."

How old are you now?