Track the transfer: Mark gave half his money to Ken. Work backwards from the final ratio.

[[model:questions/solutions/q5385.png]]

• Final ratio: Ken : Mark = \(7 : 5\)
• Mark kept half, so originally Mark = \(5 \times 2 = 10\) units
• Ken received 5 units, so originally Ken = \(7 - 5 = 2\) units
• Original Ken : Mark = \(2 : 10 = 1 : 5\)
• After transfer, new Ken : Mark = \(7 : 5\)

Final Answer: 7 : 5