Question 753825
 A boat travels for 7 hours. If it tavels 4 hours downstream and 3 hours upstream then it covers the distance of 116 km. But if it travels 3 hours downstream and 4 hours upstream, it covers the distance of 108 km. Find the speed of a boat?
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let x=speed of boat in still water
let c=speed of current
x+c=speed of boat downstream
x-c=speed of boat upstream
distance=travel time*speed
..
4(x+c)+3(x-c)=116
3(x+c)+4(x-c)=108
..
4x+4c+3x-3c=116
3x+3c+4x-4c=108
..
7x+c=116
7x-c=108
add
14x=224
x=16
speed of a boat=16 km/hr