Answer:
Magnitude of C= 
Angle=arctan(Ay+By/Ax+Bx)
Explanation:
Let
A = Axi + Ayj
B = Bxi + Byj
where i and j are unit vectors in the direction of x and y axes respectively.
C=A+B
C = (Ax + Bx)i + (Ay + By)j
The magnitude of vector C can be calculated by adding the square of magnitude of its componets and then taking sqaure root.
Magnitude of C= 
And the angle will be
Angle=arctan(Ay+By/Ax+Bx)
You really can't tell.
Power = I^2 × R = V^2 / R ( unit in Watt)
For P = I^2 × R
Where we have P directly proportional to R, increase in Power leads to increase in R
So if we have 100 will have higher resistance
For P = V^2/R
Power is inversely proportional to resistance.
So increase in Power leads to decrease in resistance.
60 watt will have a higher resistance.