A production plant tracks the cost per ton of processing food items. If the cost per ton was ₹1000 in 1978-79, ₹900 in 1979-80, ₹850 in 1980-81, and ₹680 in 1982-83, in which year did the cost per ton of food items show the maximum percentage decrease compared to its respective previous year?

In a data table, the production of rice for country Q and country R is 60 lakh tons and 54 lakh tons respectively. The production of wheat for country S and country T is 52 lakh tons and 52 lakh tons respectively. What is the ratio of the total production of rice of countries Q and R to the total production of wheat of countries S and T?

In a survey of 5 countries (P, Q, R, S, T), the rice production values are 40, 60, 54, 70, and 51 lakh tons respectively. What is the average production of rice (in lakh tons) across all 5 countries?