Answer:
decrease by 50%
Step-by-step explanation:
[tex]\frac{0.4x}{0.8y} =\frac{x}{2y}[/tex]
Decreased by 60% = (100%-60%)x = 0.4x.
Decreased by 20% = (100%-20%)x = 0.8x.
[tex]\frac{x}{y}[/tex] initial fraction, and we can see that denominator will increase 2 times, so fraction will decrease 2 times, or decrease by 50%.