Posted by nomee on .
which number should be subtracted from each of the three numbers 5, 15, and 50 so that the resulting three numbers form a geometric progression?

calculus 
Steve,
we want the ratio between consecutive terms to be constant:
(15x)/(5x) = (50x)/(15x)
(15x)(15x) = (50x)(5x)
x^2  30x + 225 = x^2  55x + 250
25x = 25
x = 1
Check
4,14,49 form a GP where r=7/2