Two plates and one cup costs $27. Three plates and four cups cost $58. Find the cost of a cup. Choose the correct answer.
A) 8 B) 7 C) 10 D) 5 E) 9.5
Let cost of 1 plate = x, let cost of 1 cup = y   2x + y = 27   y = 27 - 2x   Again,   3x + 4y = 51   3x + 4(27 - 2x) = 58   3x + 108 - 8x = 58   3x + 108 = 58 + 8x   3x + 50 = 8x   50 = 5x   10 = x   Now plug x into initial equation:   2x + y = 27   2(10) + y = 27   20 + y = 27   y = 7   Answer: 7
<result>B</result>
Two plates and one cup costs $27. Three plates and four cups cost $58. Find the cost of a cup.