Another variation on the dependency between money
now and money in the future. The difference: dollar now invested
will be more than the same dollar year later.
If you need a certain amount at some future date then
for different growth rates you will get the amount to invest now.
It let's you estimate the type of investment (i.e. by their average growth rate)
that makes this goal possible for a given amount you can afford to invest at the present.
Clearly higher growth rates IMPLY higher riskiness.