let the number of normal calculators produced in a day be $$x$$ andthe number of scientific calculators produced in a day be $$y$$
the minimum of total calculators to be produced per day is $$200\implies x+y\geq 200$$
Given, the minimum number of normal calculators to be produced per day is $$100 \implies x\geq 100$$ and
the minimum number of scientific calculators to be produced per day is $$80 \implies y\geq 80$$
Also given, the maximum number of normal calculators can be produced per day is $$200 \implies x\leq 200$$ and
the maximum number of scientific calculators can be produced per day is $$170 \implies y\leq 170$$
A normal calculator incurred a loss of $$Rs.2$$
For $$x$$ normal calculators, the loss is $$Rs.2x$$
A scientific calculator gained a profit of $$Rs.5$$
For $$xy$$ scientific calculators, the gain is $$Rs.5y$$
Therefore, profit of the manufacturer $$P=5y-2x$$
substituting the options in the equation $$P=5y-2x$$ and finding the maximum value and verifying whether the option satisfies the given constraints.
substituting option A i.e., $$(x,y)=(100,170)$$
$$x+y\geq 200\implies 100+170=270\geq 200$$ True
$$x\geq 100 $$ and $$x\leq 200$$ True
$$y\geq 80 $$ and $$x\leq 170$$ True
Hence, $$P=5y-2x = 5*170-2*100=650$$
substituting option B i.e., $$(x,y)=(200,170)$$
$$x+y\geq 200\implies 200+170=370\geq 200$$ True
$$x\geq 100 $$ and $$x\leq 200$$ True
$$y\geq 80 $$ and $$x\leq 170$$ True
Hence, $$P=5y-2x = 5*170-2*200=450$$
substituting option C i.e., $$(x,y)=(100,80)$$
$$x+y\geq 200\implies 100+80=180\geq 200$$ False
substituting option D i.e., $$(x,y)=(200,80)$$
$$x+y\geq 200\implies 200+80=280\geq 200$$ True
$$x\geq 100 $$ and $$x\leq 200$$ True
$$y\geq 80 $$ and $$x\leq 170$$ True
Hence, $$P=5y-2x = 5*80-2*200=0$$
Therefore, $$(100,170)$$ satisfies all constraints and produces the maximum value than the other options.