how many songs with an average of 3MB can be stored on a drive with 1.5 terabytes of data?

Binary sufexes are (should be) used in these calculations

$${\frac{\left({\mathtt{1.5}}{\mathtt{\,\times\,}}{{\mathtt{2}}}^{{\mathtt{40}}}\right)}{\left({\mathtt{3}}{\mathtt{\,\times\,}}{{\mathtt{2}}}^{{\mathtt{20}}}\right)}} = {\mathtt{524\,288}}$$

A terabyte has 10^12 bytes.

A megabyte has 10^6 bytes.

(1.5 x 10^12) ÷ (3 x 10^6)  =  (1.5 ÷ 3) x (10^12 ÷ 10^6)  =  (0.5) x (10^6)  =  5 x 10^5

1.5 terabytes = 1.5 x 10¹² bytes

3 megabytes = 3 x 10⁶ bytes

So....... (1.5 x 10¹² ) / (3 x 10⁶ )  = about 500,000 songs