If the average (arithmetic mean) of a and b is 45 and the average of b and c is 85, what is the value of c âˆ’ a?	Options
A) 25 B) 80 C) 90 D) 140 E) It cannot be determined from the information given
the arithmetic mean of a and b =(a+b)/2=45 -- a+b=90 --1   similarly for b+c=170 --2   subtracting 1 from 2 we have   c-a=80;   ANSWER:80
<result>B</result>
If the average (arithmetic mean) of a and b is 45 and the average of b and c is 85, what is the value of c âˆ’ a?