Checking account a charges a monthly service fee of $3 and a per-check fee of $0.02, while checking account b charges a monthly service fee of $2 and a per-check fee of $0.03. how many checks would a person have to write for the two accounts to cost the same?

.02x + 3.00 = .03x + 2.00     subtract 2.00 from both sides
.02x + 1.00 = .03x                subtract .02x from both sides
1.00 = .01x                           divide both sides by .01
100 = x

It will take 100 checks to be written for the accounts to cost the same.

It would take her 20 minutes.