startr by passing the mixed number into a fraction
[tex]10\frac{1}{2}=\frac{(2\cdot10)+1}{2}=\frac{21}{2}[/tex]divide the amount of beef into a quarter
[tex]\frac{\frac{21}{2}}{\frac{1}{4}}=\frac{21\cdot4}{2}=\frac{84}{2}=42[/tex]he can make 42 quarter pound burguers
