Two identical circular loops P and Q each of radius r are lying in...

Two identical circular loops P and Q, each of radius $r$, are separated by distance $r$ along their common axis. Current in P is $I$ and in Q is $4I$ (both clockwise as seen from O).
Point O is at the midpoint. The magnetic fields from each loop at O:
$B_1 = \frac{\mu_0 I R^2}{2(R^2 + R^2)^{3/2}}$ (from P, pointing toward Q)
$B_2 = \frac{4\mu_0 I R^2}{2(R^2 + R^2)^{3/2}}$ (from Q, pointing toward P)
$B_{net} = B_2 - B_1 = \frac{3\mu_0 I R^2}{2(2R^2)^{3/2}} = \frac{3\mu_0 I}{4\sqrt{2}R}$
Direction: towards Q.