Assuming simple interest, the formula to calculate the interest Ms. Paul paid is:
[tex]Interest=Principal\times Rate\times Time[/tex]In the problem, here are the given information:
Principal (Money borrowed) = $1,200
Rate = 18% or 0.18 in decimal form
Time = 9 months or 0.75 year.
(Take note that the time in the formula is measured in years.)
Let's plug in the given information to the interest formula above.
[tex]Interest=1,200\times0.18\times0.75[/tex]Then, solve.
[tex]Interest=162[/tex]Therefore, Ms. Paul paid interest of $162.
