70% of the mochi balls in Packet D were strawberry mochi balls and the rest were blueberry mochi balls. Packet E had 25% more strawberry mochi balls than Packet D and four times as many mochi balls than the total number of mochi balls in Packet D. Find the percentage of the blueberry mochi balls in Packet E that would need to be transferred into Packet D, so that there were an equal number of strawberry and blueberry mochi balls in Packet D.

	Packet D		Packet E
	Strawberry	Blueberry	Strawberry	Blueberry
	10 u		40 u
Before	7 u	3 u	8.75 u	31.25 u
Change		+ 4 u		- 4 u
After	7 u	7 u	8.75 u	27.25 u

70% = ⁷⁰₁₀₀ = ⁷₁₀
100 %+ 25% = 125%

 Total number of mochi balls in Packet D
= 7 u + 3 u
= 10 u

Total number of mochi balls in Packet E
= 4 x 10 u 
= 40 u

Number of strawberry mochi balls in Packet E
= 125% x 7 u
=  ¹²⁵₁₀₀ x 7 u
= 8.75 u

Number of strawberry mochi balls in Packet E
= 40 u - 8.75 u
= 31.25 u

Number of blueberry mochi balls to be transferred from Packet E to Packet D
= 7 u - 3 u
= 4 u

Percentage of mochi balls to be transferred from Packet E
= ⁴_31.25 x 100%
= 12.8%

Answer(s): 12.8%