I did the work but can someone tell me what x equals?

What is best way to getting answer for my exam is

Given: jk ||lm prove: _2 = 27 statement justification 1. jk ||lm 1. given 2.26 = 27 3.22 = 26 2. 3. 4. _2 = 27 4. corresponding angles theorem transitive property of equality vertical angles theorem substitution property of equality

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?