A concert charges $30 admission and $15 per shirt. Alyssa paid $75 at the concert for her admission and shirts. Write and solve an equation to find the number of shirts Alyssa bought. Explain what your variable represents. A. Let x = number of admission tickets; 30x + 15 = 75; 2 tickets. B. Let x = number of admission tickets; 15x + 30 = 75; 3 tickets. C. Let x = number of shirts; 30x + 15 = 75; 2 shirts. D. Let x = number of shirts; 15x + 30 = 75; 3 shirts.