two charges +q and +q are separated by a distance joining the two nuclei, if the third charge Q is placed at the centre, what will be the ratio Q/q?

Gotta have a picture ^^

The boat's velocity relative to the riverbank can be resolved into two components. the component going north is 2.7 m/s and the component going west is 1.2 m/s.we add these two vectors and then find the magnitude of the resultant to get the speed.the magnitude of the resultant vector from adding can be obtained by the pythagorean theorem.    to two significant figures, the boat's speed relative to the riverbank is 3.0 m/s.

Iwould say earthquakes.