Answer
$$T=3.1 \mathrm{\ N}$$
Work Step by Step
We apply Newton's second law to the $x$ axis of each box:
$$
\begin{aligned} m_{2}\ g\ \sin \theta-T &=m_{2}\ a \\ F+T &=m_{1}\ a \end{aligned}
$$
Adding the two equations allows us to solve for the acceleration:
$$
a=\frac{m_{2} g \sin \theta+F}{m_{1}+m_{2}}
$$
With $F=2.3 \mathrm{N}$ and $\theta=30^{\circ},$ we have $a=1.8 \mathrm{\ m} / \mathrm{s}^{2} .$
We plug back in and find $T=3.1 \mathrm{N}$
