After how many years will the costs equal the revenues Solut

After how many years will the costs equal the revenues?

Solution

The revenue y is given by the formula 4x + 12y = 180 or, 12y = 180 - 4x or, y = 15 - x/3 ...(1)

The cost y is given by the formula 6y - 2x = 70 or, 6y = 70 + 2x or, y = 70/6 + 2x/6 or, y = 35/3 + x/3...(2)

When the cost equals the revenue, we have 35/3 + x/3 = 15 - x/3 or, x/3 + x/3 = 15 - 35/3 or, 2x /3 = 10/3. Now, on multilying both the sides by 3, we have 2x = 10 or x = 5 years.