Cool puzzle!
Five numbers are in geometric progression. Their sum is 6 and the sum of their reciprocals is 3. What is their product?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Let the numbers be a / r 2 , a / r , a , a r , a r 2
The sum is now given as a ( 1 / r 2 + 1 / r + 1 + r + r 2 ) = 6
Sum of reciprocals is given by ( 1 / r 2 + 1 / r + 1 + r + r 2 ) / a = 3
Dividing the 2 equations, we get a 2 = 2
The product is given as a 5 which is 4 2