Answer:
34%
n = new % = Answer
(4kg x 16%) + (12kg x 40%) = (New Percentage(Total kg))
(.16 x 4) + (.4 x 12) = n(4 + 12)
Simplify above to get:
.64 + 4.8 = 16n
.64 + 4.8 = 5.44
5.44 = 16n
Divide both sides by 16
.34 = n
34%
Convert .34 to Percentage by moving decimal to the right 2 times.
MaybeKuro