given conditions are b+c>6 and a+b+c>9, we have to find minimum value of a for any value of b and c.
Dear sandeep,
if we take a =1 then for 6 < b+c<8, the condition a+b+c will not be valid,
similarly if a<3, then for b+c>6, a+b+c>9 will not be valid always.
but if we will take a=3 then for every pair of b and c satisfying b+c>6 , the condition a+b+c>9 will be valid