Machine A and machine B are each used to manufacture 330 sprockets. It takes machine A 10 hours longer to produce 330 sprockets than machine B. Machine B produces 10 percent more sprockets per hour than machine A. How many sprockets per hour does machine A produces? Select:
A) 5
B) 4
C) 6
D) 8
E) 3

Rationale: "machine b : takes x hours to produce 330 sprockets machine a : takes ( x + 10 ) hours to produce 330 sprockets machine b : in 1 hour , b makes 330 / x sprockets machine a : in 1 hour , a makes 330 / ( x + 10 ) sprockets equating : 1.1 ( 330 / ( x + 10 ) ) = 330 / x 484 / ( x + 10 ) = 330 / x 363 x = 330 x + 3300 33 x = 3300 x = 100 a makes 330 / ( 110 ) = 3 sprockets per hour answer : e"
Answer: E