1st payment is $37. Payments increase by$15 each month (so 36th payment = $562). How much interest has been paid? 36*(37+562)/2-8000 =2762 Last edited: #### Denis ##### Senior Member 36*(37+562)-8000 =2762 36*(37+562)-8000 = 13564 ..... korner...korner... #### Subhotosh Khan ##### Super Moderator Staff member 36*(37+562)-8000 = 13564 ..... korner...korner... Okay I'll give company for 2 minutes...... #### Denis ##### Senior Member 2 minutes over...what's your answer? #### Denis ##### Senior Member C'mon ... c'mon ... no takers? Subhotosh's 2762 is not correct... #### Romsek ##### Junior Member C'mon ... c'mon ... no takers? Subhotosh's 2762 is not correct... it's$2782

$$\displaystyle 15 \dfrac{36\cdot 35}{2}+36\cdot 37=10782 - 8000 = 2782$$

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#### Denis

##### Senior Member
it's \$2782

$$\displaystyle 15 \dfrac{36\cdot 35}{2}+36\cdot 37=10782 - 8000 = 2782$$
Yepper!
SUM(arithmetic series) - amount borrowed

Rate turns out to be 1.284% monthly (or 15.408 APR cpd. monthly).

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