Integers a, b, c, d and e satisfy 50<a<b<c<d<e<500, and a,b,c,d,e form a geometric sequence. What is the sum of all possible distinct values of a?

Answer 1

500 = 50r^6
r^6 = 10
Since r is irrational, and no power of 5 less than 6 is rational, there are no integer values between 50 and 500.

Answer 2

@Steve: what about this sequence?
64,96,144,216,324

Answer 3

the answer is 321