borrowed $500 & repaid $812.50- what was the interest rate?

Question

I was stupid and borrowed money from on-line co. Rec'd $500 on March 13. Made 3 payments and within 81 days (requested 90 day loan) paid out $812.50. Trying to figure exact interest paid b/c am fighting with them...they say I still owe them $.

Answer 1

DONT DU THAT AGIN . . interest=812.50-500$=312.5$ interest . . . %=312.5/500=62.5% av 500$ . . . BUT, time=90 daes=3 months=(1/4) yeer . . . %/yeer=4*62.5=250% . . . If yu made paements eech month, thats kompound interest. . . . % rate slitely differ from simpel interest. . .

Comments

Yeah, you'd think us educated, older adults would know better but I read and re-read fine print and figured I could eat the interest for the sake of a quick pay off in hopes of improving credit rating (now in toilet d/t unexpected illness that lead to disability after 24 yrs of working & building up high 600 credit score!) I had gotten initial interest (62.5) but for life of me couldn't remember how to get REAL rate for 3 month payout. Thank you SO much!
Plan to utilize site when needed during tutoring sessions (I'm a teacher too- makes ques. even funnier!) or when son brings home math ?'s designed specifically to make parents feel stupid!)