Answer:
Part a) 
Part b) 
Step-by-step explanation:
we know that
A reciprocal of a rational number
is obtained by changing the numerator and denominator, so the numerator becomes the denominator and the denominator becomes the numerator obtaining 
Part a) we have
200
we know that
the given number can be expressed as 
so
changing the numerator and denominator
The reciprocal is equal to 
Part b) we have
450
we know that
the given number can be expressed as 
so
changing the numerator and denominator
The reciprocal is equal to 