1] A man rows upstream 16 km and downstream 28 km taking 5 hours each time. the velocity of the current is
a] 2.4 km/hr  b] 1.2 km/hr  c] 3.6 km/hr  d] 1.8 km/hr

solution
 speed upstream = (16/5) = 3.2 km/hr
 speed downstream = (28/5) = 5.6 km/hr
velocity of current = (1/2)(3.2~ 5.6) = 1.2 km/hr


2] A man rows upstream 30 km and downstream 18 km taking 5 hours each time. What is the velocity of the current?
a] 2.4 km/hr  b] 1.2 km/hr  c] 3.6 km/hr  d] 1.8 km/hr

3] A man rows upstream 12 km and downstream 37 km taking 5 hours each time. What is the velocity of the current?
a] 4.5 km/hr  b] 2.5 km/hr  c] 3 km/hr  d] 4 km/hr