On a river, C is the mid-point between two points A and B on the same bank of the river. A boat can go from A to C and back in 14 hours and from A to B in 20 hours 20 min. How long it would take to go from B to A?

Question: On a river, C is the mid-point between two points A and B on the same bank of the river. A boat can go from A to C and back in 14 hours and from A to B in 20 hours 20 min. How long it would take to go from B to A?

Solution:
Time required to travel from A to B = 20 hour 20 min
Time required to travel from A to C = 1/2 (20 h 20 m)
= 10 h 10 m

Given total time from A to C and C to A = 14 h
∴ 10 h 10 m + C to A = 14 h
∴ C to A = 3 h 50 m

Time taken from B to A is twice of C to A
then, time taken from B to A =2 × (3 h 50 m) =7 h 40 m