Question

53) A boat covers certain distance between two spots
in a river taking t, hrs going downstream and t, hrs
going upstream. What time will be taken by boat to
cover same distance in still water?
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Answer 1

Answer:

3) 2 t1t2/t1+t2

Explanation:

Let velocity of water be u and velocity of boat in still water be v

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be d

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/v

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)d = t1v + t1 [v(t2-t1) /t1+t2)]

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)d = t1v + t1 [v(t2-t1) /t1+t2)]d(t1+t2) = t1v(t1+t2) + vt1 (t2-t1)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)d = t1v + t1 [v(t2-t1) /t1+t2)]d(t1+t2) = t1v(t1+t2) + vt1 (t2-t1)d(t1+t2) = t1vt1 + t2t1v + vt1t2 - t1t1v

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)d = t1v + t1 [v(t2-t1) /t1+t2)]d(t1+t2) = t1v(t1+t2) + vt1 (t2-t1)d(t1+t2) = t1vt1 + t2t1v + vt1t2 - t1t1vd(t1+t2) =2vt1t2

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)d = t1v + t1 [v(t2-t1) /t1+t2)]d(t1+t2) = t1v(t1+t2) + vt1 (t2-t1)d(t1+t2) = t1vt1 + t2t1v + vt1t2 - t1t1vd(t1+t2) =2vt1t2d/v = 2t1t2/( t1+t2)

Let velocity of water be u and velocity of boat in still water be vLet distance traveled be dWe need to find d/vt1= d/(v+u)d= t1 v + t1 u (1)t2= d/(v-u)d = t2 v- t2 u (2)From 1&2v t1 + u t1= v t2- u t2u(t1+ t2) = v(t2- t1)u = v(t2-t1) / (t1+t2)Substituting value of u in (1)d = t1v + t1 [v(t2-t1) /t1+t2)]d(t1+t2) = t1v(t1+t2) + vt1 (t2-t1)d(t1+t2) = t1vt1 + t2t1v + vt1t2 - t1t1vd(t1+t2) =2vt1t2d/v = 2t1t2/( t1+t2)Here d/v represents time taken by boat to cover a distance of d in still water