Question

Suppose that a vegetable vendor pays 7% interest daily on a $10 loan. Then, suppose that this individual was able to save $0.50 per day by drinking less tea. Calculate the number of days it would take for the vendor to no longer need to borrow money in order to purchase $10 of vegetables (i.e. the day number on which no loan is needed).

Answer 1

n=the day number on which no loan is needed?
r= interest daily=7%=0.07
Pv=(daily)=$0.5
Future Value=Fv=$10
n=ln(Fv/Pv)/ln(1+r)
Using http://www.mathsisfun.com/money/compound-interest-calculator.html
n=ln(10/0.5)/ln(1+0.07/)=

Answer 2

2.995732274

Answer 3

0.067658648

Answer 4

29.49707588

Answer 5

so i am guessing 29 days

Answer 6

but which turns out to be wrong

Answer 7

n= (log FV- log PV)/ log(1+r)