Hmm

Note, Solveit.......the sum of the interior angles of any quadrilateral  = 360°

So .....angles A + B + C + D  = 360°    (1)

A =  2 times angle B →   B  = A/2

A =  4 times angle C →   C  = A/4

A =8 times angle D →   D = A/8

So....substituting into (1)

A + A/2 + A/4 + A/8  = 360°   get a common denominator

[8A + 4A + 2A + A] / 8 = 360°       simplify the left side

15A / 8 =   360°      multiply both sides by 8

15A  =  2880°     divide both sides by 15

A = 192°

So....D  = A/8  = 192° / 8     =   24°    (E)

aaaa thanks CPhill ! :)