Question 1111155
{{{ ((a[1]+a[2]+a[3]+a[4]+a[5]+a[6])/6) = 4 }}}

Without loss of generality, say {{{ a[6] = 2 }}}

{{{ ((a[1]+a[2]+a[3]+a[4]+a[5] + 2)/6) = 4 }}} 
{{{ (a[1]+a[2]+a[3]+a[4]+a[5]) = 24-2 = 22 }}}

average = {{{ ((a[1]+a[2]+a[3]+a[4]+a[5])/5) = 22/5 = highlight(4.4) }}}