how many cubic mitres are there in 1 ton of asphalt

If we assume the density of asphalt is about 2000kg/m³, and 1 ton = 907kg then

volume = 907/2000 m³

For a thickness of 166mm (=0.166m) the area covered is

$${\mathtt{area}} = {\frac{{\mathtt{907}}}{\left({\mathtt{2\,000}}{\mathtt{\,\times\,}}{\mathtt{0.166}}\right)}} \Rightarrow {\mathtt{area}} = {\mathtt{2.731\: \!927\: \!710\: \!843\: \!373\: \!5}}$$

or area ≈ 2.7 m²