In 10 years' time,Mrs smith will be 57 years old .how old was she five years ago?

57 - 10 - 5 = ?

42 years old

To find out how old Mrs. Smith was five years ago, we need to subtract 5 from her age in 10 years.

Since we know that in 10 years, Mrs. Smith will be 57 years old, we subtract 5 from 57:

57 - 5 = 52

Therefore, Mrs. Smith was 52 years old five years ago.