The area of a wound shrinks by 5% each day. How long will it take for the wound to shrink to 10% of its initial size?
+118723 The area of a wound shrinks by 5% each day. How long will it take for the wound to shrink to 10% of its initial size?
0.9=1(0.95)^n
log0.9=log(0.95)^n
log0.9=n*log(0.95)
log0.9 / log0.95=n
log(0.9)/log(0.95) = 2.0540797177456861 days
2.0540797177456861*24 = 49.2979132258964664 hour
0.2979132258964664*60 = 17.874793553787984
2 days 1 hour and 18 minutes to the nearest minute. 
I think Melody misread the question. The question REALLY asks how long before the wound is 90% smaller.
There are two ways to answer this, depending on what you are learning these days.....if the wound shrinks a contant amount of the original each day (5%) then we need to find how many days to shrink 90%
90/5 = 18 days.
If the wound shrinks 5% of the wound area on THAT day, a different answer will result: As per Melody's method
0.1 = 1(0.95)^n
log0.1/log0.95 = n = 44.89 days (I think)
