A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the same direction has a speed of

6m/s

Explanation:

The mosquito will have a speed of 6 m/s.

if the speed of the mosquito and breeze was in opposite direction, we will subtracted them from each other and the result will be the speed of mosquito moving in the direction of the higher speed (between the breeze and mosquito). while if they are both moving in the same direction the speed of the mosquito will be the sum of both the speed of the mosquito and breeze thus the mosquito and breeze are moving in the same direction so we just sum it up (3m/s + 3m/s = 6m/s).