150 being the rental cost and if it is 15 dollars per person you have to multiply 15 by the amount of people going so it is 15x and 400 is the maximum amount of money to pay.
There are 3 meals and if she feeds her lion 6/9 each meal, you would multiply by 3. 6/9 multiplied by 3 would be 18/9. If you divide 18/9 by 1/9, you get 18.