Josh bought 800 plastic whistles to give away to the kids at a street fair. some of the whistles were small and cost $0.50. the larger whistles cost $0.75. in total, he spent $550 on the whistles. how many of the small whistles did he buy?

200 small whistles.

Explanation:

This is a system of equations for this problem, where s refers to small whistles and l refers to large whistles. The first equation represents the added costs of the whistles equaling the total cost, and the second equation represents the added amount of whistles purchased equaling the total amount of whistles.

To solve, simply isolate the second equation for l.

Next, substitute your new value of l into the first equation and simply.

Once complete, you'll have solved for your s value (200), which is your answer.