Answer
The normal force on each rear wheel is $~~2400~N$
Work Step by Step
We can choose a rotation axis at the front tires and consider the torque about this axis.
We can find the total normal force on the rear wheels:
$\sum~\tau = 0$
$L~F_N - d~mg = 0$
$F_N = \frac{d~mg}{L}$
$F_N = \frac{(1.8~m)~(11,000~N)}{4.2~m}$
$F_N = 4714~N$
Since the normal force on each rear wheel is $\frac{F_N}{2}$, the normal force on each rear wheel is $~~2400~N$
