Dividing a flock among three sons

Three brothers inherit a flock. Alfred's share exceeds John's by $20\%$ and exceeds Charles's by $25\%$. John receives $3600$ sheep. How many sheep go to Charles?

3456. Alfred has $1.2\times3600=4320$ sheep. Since this is $1.25$ times Charles's share, Charles has $4320/1.25=3456$.