The fraction will change by 200%.
Let the fraction is = x/y.
If its numerator is decreased by 10% then the new numerator is:
x - 10% of x
= x - 0.10x
= 0.90x
If its denominator is decreased by 70% then the new denominator is:
y - 70% of y
= y - 0.70y
= 0.30y
So the new fraction is = .
So the change in fraction is in percentage is:
So the fraction will change by 200%.