Cash advance fee:
2% of $200 = 0.02 * 200.00 = $4.00
One month's interest, if the interest is compounded monthly:
18% of $204.00, divided by 12 months/year = 0.18 * 204.00 / 12 = $3.06
Total paid:
$200 + $4 + $3.06 = $207.06
Paying directly with the card instead of borrowing cash would have saved the $4 charge and would also have reduced the interest from $3.06 to $3.00.
Paying directly with the card and then paying before the billing cycle would also save the $3.00.She would only have paid the original $200, saving the whole $7.04.
Effect of paying directly with the card and paying it off before the billing cycle: $200 total paid, saving $7.04 in fees and interest.