Solving for a current using node-voltage analysis
If you wish to solve this question using Nodal analysis then this is how to go about it:

Consider the black dot on the top to be one of your Nodes. Lets call this Node A.
The other black dot becomes our Datum Node or the Node at Ground Voltage (Node B).

Next we will assume another current \$i_b\$ flowing from ground to Node A



Applying Kirchoff's Current Law at node A, we get:

$$i_b + 1 = i_a$$

Now we write this in terms of Voltages using Ohm's Law (\$V=IR\$)

Therefore,

$$\frac{0+10-V_a}{10} + 1 = \frac{V_a}{5}$$

On solving this you get \$V_a = 20/3\$ Volts.

Therefore current \$i_a = V_a/5 = 20/(5 \times 3) = 4/3 = 1.33\$ A