We have:
Total pizzas: 20
They sell: 8 and 1/4
7 and 5/10
Then, We add up what they sold in the first and second hour:
[tex]8\frac{1}{4}+7\frac{5}{10}=\frac{33}{4}+\frac{15}{2}[/tex]Multiply and divide the second fraction by 2:
[tex]\frac{33}{4}+\frac{15}{2}\cdot\frac{2}{2}=\frac{33}{4}+\frac{30}{4}[/tex]Then, Add the fractions:
[tex]\frac{33+30}{4}=\frac{63}{4}[/tex]This is that they sell 63/4 pizzas. Therefore, they still have left to sell:
[tex]20-\frac{63}{4}=\frac{17}{4}=4\frac{1}{4}[/tex]Answer: they still have left to sell 4 and 1/4 pizzas
