there s a table of daily expenses and we are asked to find the rate of inflation..how to proceed?

Inflation Rate is the rate of change of prices. So just calculate the difference between the periods for which inflation rate has been asked and then find the percentage, taking the first value as the base. For example, say the average value of prices has changed from 20 to 22 so rate of inflation would be (2/20)*100 = 10%.
Hope that helps.