a) If we imagine our wire and grab it elongating our thumb we see that if the line of the field is pointing to the east above the wire, then the current must run $boxed{north}$.

b) We can apply the same reasoning but this time we will place the compass below the wire. Now the needle will point $boxed{west}$.

$$
B=frac{mu_0 I}{2pi r}propto frac{1}{r}
$$

a) In the first case we have that

$$
frac{B_1}{B_2}=frac{frac{1}{r_1}}{frac{1}{r_2}}=frac{r_2}{r_1}=frac{2}{1}
$$

Finally, we have that

$$
boxed{frac{B_1}{B_2}=2}
$$

So the initial field is two times stronger.

b) In the second case, we have the same procedure which gives

$$
frac{B_1}{B_2}=frac{3}{1}
$$

$$
boxed{frac{B_1}{B_2}=3}
$$

So the initial field is three times stronger.