Initially....let the total number of beads between them = N
So, at first, Robert has (1/5)N and Robin has (4/5)N
When Robert loses (1/5) of his he has (1/5)(4/5)N = (4/25) N
Then Robin gives him 152 so he has (4/25)N + 152
And Robin now has (4/5)N - 152....so....
(4/25)N + 152 = (4/5)N - 152
(4/25)N + (4/5)N = 152 + 152
(4/25)N + (20/25)N = 304
(24/25)N = 304
N = 304 ( 25/24) = 1900
Robin had 1900 (4/5) = 1520 beads at first
