If a credit card company charges 2% per month, how much would a person have to pay in interest for an amount of $1000 pending for a year at the...

The basic approach in the answer #1 above is correct.
However, the rate of interest assumed in the equation used is in terms of per unit
rather than percentage.

Also please that the interest is
compounded every month in line with general practice adopted by credit card
companies.

When:

r =
percentage rate of interest per month = 2

n = number of
months = 12 (given)

p = Principal amount of loan =
$1000

The total amount of principle plus interest payable
after n months is given by:

Total amount = p*(1 +
r/100)^n

Substituting the given values in the above
equation:

Total amount = 1000*(1 +
2/100)^12

= 1000*1.02^12

=
1000*1.26824

=
1268.24

Interest paid = (Total amount) -
Principal

= 1268.24 - 1000

=
268.24

Interest = $268.24