Ok, so the sh hasip velocity with northward component and eastward component.
The current only has eastward component.
First you want to find the magnitudes of the components, add them together and then use Pythagoras theorem to find the resultant.
Eastward component of velocity of boat: 5*sin20 = 1.710...
Add the component to the current: 1.71...+ 1 = 2.710...
You also need to find the northward component of the ship: 5*cos20 = 4.698...
Now use use Pythagoras theorem: R = sqr[(2.710...)^2 + (4.698...)^2] = 5.4240...
R is the resultant velocity, and sqr is square root