Explanation:

- We have the ratio P:Q as 4:5.

- Given, Q = 300.

- Using the ratio, P = (4/5) * Q = (4/5) * 300 = 240.

- R is 15% less than Q, so R = Q - (15/100) * Q = 300 - 45 = 255.

- The sum of P and R is 240 + 255 = 495.

- Option 1: 515 (Incorrect)

- Option 2: 485 (Incorrect)

- Option 3: 495 (Correct)

- Option 4: 475 (Incorrect)

- The correct answer is Option 3: 495.