48 x 1/3 is literally 48 ÷ 3, or 16.
2/5 x 7/4 I usually multiply the numerators and multiply the denominators:
[tex]\frac{2 * 7}{5 * 4} = \frac{14}{20} = \frac(7}{10}[/tex]
1/2 x 1/4 is the same, ends up 1/8.
Does this make sense? Do you need any more help?