If the average (arithmetic mean) of a and b is 20, and c – a = 30, what is the average of b and c?	Choose the correct choice from the following
A) 25 B) 30 C) 40 D) 35 E) 45
a+b/2 = 20   =&gt; a+b = 40   a = c - 30...sub this value   c-30+b = 40   =&gt;c+b = 70   =&gt;c+b/2 = 35   Answer : 35
<result>D</result>
If the average (arithmetic mean) of a and b is 20, and c – a = 30, what is the average of b and c?