D. 2:1
Feedback Number of litres of sugar solution in the mixture = (1/(1+2)) *45 = 15 litres.
So, 45-15 = 30 litres of salt solution is present in it.
Let the quantity of sugar solution to be added be x litres.
Setting up the proportion,
sugar solution / salt solution = (15+x)/30 = 2/1 ? x = 45.
Therefore, 45 litres of sugar solution has to be added to bring it to the ratio 2:1.