I believe the correct form of the given equation is:
I = square root (W / R) ---> where both W and R is inside the square root symbol
where,
I = the current
W = the electric power
R = resistance in ohms
Now to solve for the value of I for each set, simply substitute the values of W and R into the equation, that is:
when W=100,R=25
I = square root (100 / 25)
I = square root (4)
I = 2
when W=100,R=50
I = square root (100 / 50)
I = square root (2)
I = 1.414