What is the average of all the multiples of 6 from 20 to 80?

From 20 to 80 ,

First term multiple of 6 = 24 & Last term multiple of 6 = 78

Average = \(\frac{First\; term \;+\; Last \;term }{2}\)

= \(\frac{24 \;+\; 78 }{2}\)

= \(\frac{102 }{2}\) = 51