Question

If sum of upstream and downstream speed of a boat is 82 kmph, and the boat travels 105 km. upstream in 3 hr, Find the time taken by boat to cover 141 km downstream.

• A. 5 hrs
• B. 3 hrs
• C. 4 hrs
• D. 2 hrs

Answer 1

Answer:

B. 3 hrs

Speed of Upstream =u-v

Speed of Downstream = u+v

Given,

Speed of upstream and downstream is

u-v+u+v=82

2u=82

Speed of Upstream, u=41km/hr.

41 – v = $\frac{105}{3}$ = 35

v = 6 km/hr

then,

u + v= $\frac{141}{t}$

41 + 6 = $\frac{141}{t}$

t = $\frac{141}{47}$ = 3 hrs.