she sold 2 trays, and each tray contains 12 meat slices and 19 cheese slices
Explanation
Step 1
Let
Each party tray contained the same number of meat slices,so
the total number of party trays and slices of meat and cheese Doris sold is
[tex]\begin{gathered} a\text{ }party\text{ tray}\Rightarrow xmeat\text{ slices +y ch}esse \\ \text{total sold trays}\Rightarrow24+38 \\ \text{then factorize} \\ 24+38\Rightarrow2(12+19) \end{gathered}[/tex]it means she sold 2 trays, and each tray contains 12 meat slices and 19 cheese slices
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