A dyes is made by mixing red and yellow colors in the ratio of 2 ∶ 5. If the amount of red color in the dye is increased by 25%, what will be the percentage of yellow color in the new dye to be made?

Correct option is C

Given
Initial Ratio Red : Yellow = 2 : 5
Red increased by 25%

Solution
Let initial amount of Red = 200 units, Yellow = 500 units.
New Red = 200 + 25% \text{ of } 200 = 200 + 50 = 250
Yellow remains 500.
Total new weight = 250 + 500 = 750
Percentage of Yellow = $$\frac{500}{750} \times 100$$​​
Percentage = $$\frac{2}{3} \times 100 = 66.67\%$$​​

Final Answer
So the correct answer is (c)