If two distinct lines in a system of linear equations are parallel, they .

1 point
a.
have the same slope and an infinite number of solutions
b.
have different slopes with one solution
c.
have the same slope and no solution
d.
have different slopes with no solution

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?