On a river , Q is the mid - point between two points P and R on the same bank of the river. A boat can go from P to Q and back in 12 hours, and from P to R in 16 hours 40 minutes. How long would it take to go from R to P?

• A. ${\text{3}}\frac{3}{7}$$ hr
• B. hr
• C. ${\text{6}}\frac{2}{3}$$ hr
• D. ${\text{7}}\frac{1}{3}$$ hr