Given data:
The number of red drops for first batch are r=100.
The number of blue drops for first batch are b=20.
The number of red drops for second batch are r'=75.
The number of blue drops for second batch are b'=15.
The expression for the red per blue drop for first batch is,
n=r/b
Substitute the given values in the above expression.
n=100/20
=5
The expression for the red drop per blue drop of the second batch is,
n'=r'/b'
Substitute the given values in the above expression.
n'=75/15
=5
Thus, yes the ratio of red to the blue drop is same for both batches.