Tony, Ken and Steve had some marbles. Tony had 4/5 as many marbles as Ken. Ken had 3/5 as many marbles as Steve. After Tony gave 36 marbles to Ken, the ratio of Tony's marbles to Ken's became 5:7. How many more marbles did Steve have than Ken in the end?

Answer 1

At the start:
Steve --- x
Ken ----- 3x/5
Tony --- (4/5)(3x/5) = 12x/25

after the give-aways
Tony --- 12x/25 - 36
Ken --- 3x/5 + 36

(12x/5 - 36) / (3x/5 + 36) = 5/7
cross-multiply
84x/5 - 252 = 15x/5 + 180
69x/5 = 432
x = 432(5/69) = not a whole number.

Find my error or else the question is bogus.

Answer 2

t = 4/5 k
k = 3/5 s
(t-36)/(k+36) = 5/7
solve to get
k = 720
s = 1200
t = 576
so, s-k = 540/756 1200-756 = 444

Answer 3

Found my error, a copy error

(12x/5 - 36) / (3x/5 + 36) = 5/7
should have been
(12x/25 - 36) / (3x/5 + 36) = 5/7