Thousand solid metallic spheres of diameter 6 cm are melted and recast into a new solid sphere. The diameter of the new sphere (in cm ) is
30
90
45
45
1980
1981
1983
1983
500 tonnes
1000 tonnes
5000 tonnes
5000 tonnes
15%
30%
50%
50%
1980 and 1981
1982 and 1983
1984 and 1985
1984 and 1985
A.
1980 and 1981
Clearly it can be concluded from the graph that rate of change of production of food grain is minimum in 1980 and 1981.