A solution contains 30% of substance S and 70% of substance T by weight. If the solution has a total mass of 1200 grams, and 300 grams of substance S are added to it, what is the new percentage concentration of substance S in the solution?

Correct option is B

Given
Initial total mass of solution = 1200 g
Initial percentage of Substance S = 30%
Mass of Substance S added = 300 g

Formula Used
Mass of substance = $$Percentage \times Total \ Mass$$​​
New Percentage =  $$\frac{\text{New Mass of Substance}}{\text{New Total Mass}} \times 100$$​​

Solution
Calculate the initial mass of Substance S:
Initial mass of S = $$\frac{30}{100} \times 1200 = 360 g$$​​
Add the new amount of Substance S:
New mass of S = 360 + 300 = 660 g
Calculate the new total mass of the solution:
New total mass = 1200 + 300 = 1500 g
Find the new percentage concentration of S:
New Percentage = $$\frac{660}{1500} \times 100$$​​

New Percentage = $$\frac{66}{150} \times 100 = 44\%$$​​

Final Answer
So the correct answer is (b)