Suppose that a sum of money at simple interest becomes $840 in 1
year and $960 in 4 years. What is the principal?
960-840 - 120 interest in 3 years. That's $40/yr
So if you had 840 at the end of the first year you must have started with _______?
year and $960 in 4 years. What is the principal?
So if you had 840 at the end of the first year you must have started with _______?