Cost of repairing shoes for 1 year=1250
Cost of purchasing new shoes for 1 year=1400(since 2800 for 2 years)
Let cost per year of the new shoes is x% greater than cost of repairing used shoes.
Then,1400 is x% greater than 1250.
1400=(1+x/100)*1250
Now,1+x/100=1400/1250
1+x/100=1.12
x/100=.12
x=12