A boat takes 7 hours to move 63 km downstream and 30 km

Solution

Let the Speed of the boat in still water B And Speed of Stream =S Let downstream speed be (B+ S) and upstream speed be (B - S) Now, By multiplying 8 with eq (i) and 5 with eq (ii) we get Subtracting eq (iv) from eq (iii) we get, B+S =364/26 B+S =14 Putting the of (u + v) in eq (ii) we get, B-S =12. Now, To move 35 km downstream and 27 km upstream time = 35/14 + 27/12 =2.5+ 2.25        =4.75 =4 hours 0.75×60 minutes. =4 hours 45 minutes.