Question

a boat goes 64 km upstream and 72 km downstream in 14 hrs. It goes 80 km upstream and 96 km downstream in 18 hrs. find the speed of boat in still water and that of current. pls fast.​

Answer 1

Let the speed of boat in still water be x and speed of stream be y 

64/ ( x-y) + 72 / (x+y) = 14 

80/ (x-y) + 96 / (x+y) = 18 

Let x-y be = a and x+y be = b 

64/ a + 72/b = 14 

80/a + 96/b =18 

MULTIPLY EQUATION 1 BY 4 AND EQUATION 2 BY 3 

256/a + 288/b = 56 

240/a + 288/b = 54 

SUBTRACT 16/a = 2 

a= 8 

240/8 + 288/b = 54 

288/b = 24 

b = 12 

x+y = 12 

x-y = 8 

ADD 2x = 20 

x =10 km/ hour y = 2 km/ hour ANSWER 

CHECK 

64/ (10-2) + 72 / (10+2) = 8 + 5= 14 hours........

Pls mark brainliest