Give me a trick on how to multiply a fraction by a while number

An energy plant is looking into putting in a system to remove harmful pollutants from its emissions going into earth's atmosphere. the cost of removing the pollutants can be modeled using the function c = 25000p/100 -p what is the vertical asymptote?

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30

The ratio of the perimeters of two similar triangles is 4: 3. what are the areas of these triangles if the sum of their areas is 130cm2?