This is the 2607th most frequent Spanish word.
cuánto
"Cuánto" means "how much" or "how many."
In this sentence, 'cuánto' is used as an interrogative to inquire about the price or cost of an item.
¿Cuánto cuesta este libro?
How much does this book cost?
Here, 'cuántos' is used as an interrogative quantifier to ask or reference the specific number associated with an entity, in this case, 'years'.
No sé cuántos años tiene ella.
I don't know how many years old she is.
In this example, 'cuánto' is used to question the amount or quantity of time remaining.