Answer:
9.4 m/s
Explanation:
This is the concept of application of the Pythagorean theorem. The resultant speed of the motorboat which is crossing the river that has a northward current of 5 m/s at a speed of 8 m/s will be given by:
c^2=a^2+b^2
c^2=8^2+5^2
c^2=64+25
c^2=89
c=sqrt89
c=9.4 m/s