the number 6 is halfway between 2.8 and what?
2*6 - 2.8 = 12 - 2.8 = 9.2
( 2.8 + x )/2 = 61.4 + x/2 = 6x = 6 - 1.4 = 4.6= 4.6 * 2= 9.2