Two pounds of cashews cost $5, 3 pounds of cashews cost $7.50, and 8 pounds of cashews cost $20. Find the constant of proportionality. Then write an equation that represents the relationship between the cost and the number of pounds cashew.

The students at jefferson middle school are raising money for a charity by selling t-shirts and hats. the number of t-shirts sold was 3 times the number of hats. the profit was $5 for each t-shirt sold and $2.50 for each hat sold. the students raised $840 for the charity. they used the system below to analyze their success and found the solution to be (144, 48). 5x+2.50y=840 x=3y how much did they earn from t-shirt sales?