Help me with my maths homework!!

This is the only question that I don't understand from my homework
So like can you guys help me??

Here is the question:
During a game the players can win and lose. At the start of the game Rob, Tim and Zak share the counters in the ratio of 5 : 6 : 7. At the end of the game Rob, Tim and Zak share the same number of counters in the ratio of 7 : 8 : 9. Show that Rob ends the game with more counters than he started.

another way of showing would be

since it says the same number of counters for both ratios, as above did, add up each ratio. For the start, the ratios add up to 18. For the 2nd, they add up to 24. The LCM (any multiple works) of 18 and 24 is 72. You can assume there are 72 counters (this is show that, so plugging in figures should be allowed).

5:6:7 of 72 is 20:24:28. Rob has 20 counters at the start.
7:8:9 of 72 is 21:24:27. Rob now has 21. 21>20, so he has more than he started with.

This is how I would do it add together 5 6 and 7 to get 18. Then add together 7, 8 and 9 to get 24.
24/18 is 4/3. Multiply 5 by 4/3 to get 6.666 which is lower than 7.

This is the only question that I don't understand from my homework
So like can you guys help me??

Here is the question:
During a game the players can win and lose. At the start of the game Rob, Tim and Zak share the counters in the ratio of 5 : 6 : 7. At the end of the game Rob, Tim and Zak share the same number of counters in the ratio of 7 : 8 : 9. Show that Rob ends the game with more counters than he started.