The waves used by a microwave oven to cook food have a frequency of 2.45 x 10 (to the 9th power) HZ. Calculate the wavelength of this type of wave.

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.

'b ' is the correct conclusion.