(2) Substitute the area of the magnetic ring into the formula.

Get: n = 80 times 5× 10 to the eighth power. N equals 625000.

Using proportional distribution method, 625000×2/5 = 250000.

625,000× 5 1 = 125,000

A: Each of us needs 250,000 gray tiles.

Blue tiles 125000

Expect to adopt with pure hands