Answer :
A medical company had planed to fill 20 litre of cough syrup .
So,
Total number of small bottles of capacity 125 ml of each used to fill 20 litre of cough syrup = = 160
And
Total number of small bottles of capacity 100 ml of each used to fill 20 litre of cough syrup = = 200
So,
Total number of bottles more required = 200 - 160 = 40 ( Ans )