Acomputer store sells both tablets and laptops. one brand of tablets cost $200. that same brand of laptop costs $400 . the store manager wants to sell enough of this brand of tablets and laptops to reach the sales goal of $20,000

The equation that models this situation is:

               200x+400y=20000

Let x denote the number of tablets sold.

and y denote the number of laptops sold.

Now, it is given  that:

One brand of tablets cost $200.

This means that if x tablets were sold then the cost obtained from tablets is: $ 200x

Also,

That same brand of laptop costs $400 .

This means that if y laptops were sold then the cost obtained from laptops is: $ 400y

The store manager wants to sell enough of this brand of tablets and laptops to reach the sales goal of $20,000.

This means that the total cost must be equal to 20,000

i.e.

       200x+400y=20000