42/50 in simplest form

She is correct that's how you do it to get the answer your looking for

To find the simpliest form of a fraction, all you need to do is divide the numerator and denominator by their greatest common factor, in which in this case, is 2. And so all you need to do is divide the numerator (42) and the denominator (50) by 2, to get 21/25. This means that the simpliest form of 42/50 is 21/25.