Question 1176673
he gives you 840.
one month later, you pay him 1472.


the interest charge for one month was 1472 - 840 = 632.


if that was the interest charge for one month, then the interest charge for one year would have been 632 * 12 = 7584.


the interest rate for one month was 632 / 840 = .7523809524 = 78.23809524%.


the interest rate for one year would have been (632 * 12) / 840 = 7584 / 840 = 9.028571429 = 902.9581420%.