The boat covered 46 km along the river and 17 km against the current

The boat covered 46 km along the river and 17 km against the current, took 3 hours for the whole journey. Find your own speed of the boat if the river speed is 3 km / h

Let x be the speed of the boat, then
х + 3 – speed of the boat along the river,
x – 3 – speed upstream,
Based on the data in the problem statement, we will compose an equation and determine what the boat’s own speed is equal to:
46 / (x + 3) + 17 / (x – 3) = 3
Let us bring the fractions to a common denominator.
(46 x -138 + 17x + 51) / x2 – 9 = 3
3x ^ 2 – 36 = 63x – 87
3x ^ 2 – 63x + 60 = 0
x ^ 2 – 21x + 20 = 0
D = 441 – 80 = 361
√D = 19
x1 = (21 + 19) / 2 = 20
x2 = (21 – 19) / 2 = 1
The speed of the boat cannot be 1 km / h, since the speed of the river is 3 km / h, so the speed of the boat is 20 km / h.
Answer: the speed of the boat is 20 km / h.