what is the average ( arithmetic mean ) of 10 , 2030 , 4050 , 6070 , 8090 ? Choose the most appropriate option
A) 90	B) 95	C) 70	D) 85	E) 50

Rationale: so addition of all term - 10 , 20 , 30 , . . . . . . . 90 so average = ( 10 + 20 + 30 + 40 + 50 + 60 + 70 + 80 + 90 ) / 9 = ( 450 ) / 9 = 50 hence , the correct answer is e .
Answer: E