Answer:
Let the price before increase be 100
Increased price =25percent of 100
25/100*100+100=125
When the price is increased to 125 she has to reduce 25
When the price is increased to 1 she has to reduce 25/125
Rate by which consumption decreases=25/125*100
=20 percent
Therefore she has to reduce 20percent consumption of onion so that there will be no change in her expenditure