In the morning, Marco sold 12 cups of lemonade for $3. By the end of the day, he had earned $9. How many cups of lemonade did he sell in all?

Kaycee wrote the proportion 12/3 = 9/c for this situation.

Identify the error and give two ways to write the proportion correctly.

Kaycee did not keep lemonade and dollars in corresponding positions in the ratios of the proportion. The proportion should be 12/3=c/9 or it could be written 3/12=9/c. Dollars should be in the same position and cups should be in the same position across ratios.

Step-by-step explanation:

10000000000% sure

In kaycee's she wrote 12/3 = 9/c, which was supposed to be 12/3 = c/9 or 3/12 = 9/c

The two ways to write the proportion are,

12/3 = c/9

or 3/12 = 9/c