Box A = 8 10 has 2700× 30% sunspots, and box B = 1080 has 1200× 90% sunspots.

Later, box A sunspots accounted for 40%, and box B sunspots accounted for 90%.

Suppose later, two boxes of sunspots accounted for 40%.

Then box B has (810+1080-3900× 40%) ⊙ (90%-40%) = 660 pieces.

Box B 1200-660 = 540 pieces.