Question 30194
This is the case of Simple interest or SI so we use the formulae

SI = PRT/100

here P = principle,
     R = rate of interest 
     T = time
     SI = simple interet
in the question we are given ,,,,

principle = 12,200
rate of interest = 2%
time = ?(we need to find)
simple interest = 610.00

so just apply these deatils in the above formula and you will get your answer..

Still if you won't be able to solve further, contact me again. 

hope this will help you 

Please feel free to revert back for any further queries.