The average (arithmetic mean) of two numbers is \(a\). If one of the numbers is 10, what is the other?
(A)\(2a + 10\) (B)\(2a - 10\) (C)\(2(a - 10)\) (D)\(\frac { 10 + a } { 2 } \) (E)\(\frac { 10 - a } { 2 } \)
B