A boat can travel 42 km in 6 hours while going upstream. If the speed of the stream is 2 km/h, then how much distance will the boat cover in 12 hours while going downstream?

Let's assume the speed of boat in still water and the speed of the stream is 'B' and 'C' respectively.

A boat can travel 42 km in 6 hours while going upstream.

speed of boat in upstream = $$\frac{distance}{time}$$

B-C = $$\frac{42}{6}$$

B-C = 7

If the speed of the stream is 2 km/h.

C = 2 km/h

B-2 = 7

B = 7+2 = 9 km/h

Distance covered by boat cover in 12 hours while going downstream = speed of boat in downstream $$\times$$ time

= $$(B+C)\times12$$

= $$(9+2)\times12$$

= $$11\times12$$

= 132 km