0

In one of the Hey Arnold show one character calculates amount of money that needs to be returned after a loan this way:

"A ten dollar loan over two weeks at 8% a day. That's $18.47"

I wonder how he get this number? Complex percent is calculated like this: 10 * (1 + 0.08)^14 which gives approx 29.37

Even if we assume, that weekends are not taken into consideration (calculating over 10 days, not 14), that would be 21.59

If percent is simple, that would be 10 + 10 * 0.08 * 14 = 21.2 or 10 + 10 * 0.08 * 10 = 18

But where the number 18.47 comes from?

insipidintegrator
  • 6,642
eugenekr
  • 101

1 Answers1

1

The number $18.47 that was calculated in the Hey Arnold show doesn't seem to correspond to the correct result of either simple or compound interest calculations. It's likely that the number was either a mistake or an approximation made for the sake of the show's plot.

As you pointed out, the correct calculation for compound interest would be:

$10 * (1 + 0.08)^{14} \approx 29.37$

And for simple interest, it would be:

$10 + 10 * 0.08 * 14 = 21.20$

If we consider weekends not being taken into account and only consider 10 days:

Compound interest: $10 * (1 + 0.08)^{10} \approx 21.59$

Simple interest: $10 + 10 * 0.08 * 10 = 18.00$

None of these results match the $18.47 mentioned in the show.

Lexponent
  • 127