Name: Andy
Who is asking: Parent
Level of the question: Secondary

Question: A plant increases its height by 1/2 the first day, 1/3 the second day, 1/4 the third day and so on. How many days did it take to grow to 100 times its height?


Hi Andy. This is a fun and surprisingly easy question once you see the trick.

Notice that if you multiply the height by the growth factor of the first day, that would be 3/2. The next day, you multiply by 4/3....

Now "n" is what interests us (because n-2 is the number of days it takes to grow to 100 times its original size).

So look at that equation and do some cancelling!

Stephen La Rocque>