Question

Tony is comparing two checking accounts. one has a monthly fee of $15 and a per-check fee of $0.20, and the other has a monthly fee of $20 and a per-check fee of $0.10. what is the minimum number of checks tony needs to write for the second bank to be a better option?

Answer 1

$20 minus $15 = $5 difference
$5 divided by $0.20 = 25 checks
*Now the accounts are even, except I haven't done the checks for the second account.*
25 checks times $0.10 = $2.50
$2.50 divided by $0.20 = 12.5 checks (round up in this case to 13)
*Now, you need to do 13 more checks on the second account*
13 checks times $0.10 = $1.30
$1.30 divided by $0.20 = 6.5 checks (round up in this case to 7)
*Now, you need to do 7 more checks on the second account*
7 checks times $0.10 = $0.70
$0.70 divided by $0.20 = 3.5 checks (round up in this case to 4)
*Now, you need to do 7 more checks on the second account*
4 checks times $0.10 = $0.40
$0.40 divided by $0.20 = 2 checks
*Now, you need to do 2 more checks on the second account*
2 checks times $0.10 = $0.20
$0.20 divided by $0.20 = 1 check
*Now, you need to do 1 more checks on the second account*
1 checks times $0.10 = $0.10
$0.10 divided by $0.20 = 0.5 checks (round up in this case to 1)
*Now, you need to do 1 more checks on the second account*
1 checks times $0.10 = $0.10
$0.10 divided by $0.20 = 0.5 checks
25 + 13 + 7 + 4 + 2 + 1 + 1 = 53 checks

Check your work!
Account #1- $15 + (53 times $0.20) = $25.60
Account #2- $20 + (53 times $0.10) = $25.30

Answer
53 checks