A waiter's salary consists of his salary and tips. During one week his tips were 5/2 of his salary. What fraction of his income came from tips ? Choose one.
A) 4 / 9 B) 5 / 4 C) 5 / 8 D) 5 / 7 E) 6 / 9

Rationale: income = salary ( s ) + tips = s + s * 5 / 2 = s * 7 / 2 tips = s * 7 / 2 fraction of his income came from tips = ( s * 5 / 2 ) / ( s * 7 / 2 ) = 5 / 7 answer : d
Answer: D