The amount of interest ( i ) karl will earn on the amount of principal ( p ) he has in his bank account is found by using the formula i = prt , with r representing the rate of interest and t the time the money will be in the account. sheena has twice the amount of principal as karl in a bank account at the same rate for the same amount of time. how does the interest earned on sheena's principal compare to the interest that will be earned on karl's principal?