Answer:
3 students are eating lunches other than salads and sandwiches.
Explanation:
To solve this you know that there are 18 students in the cafeteria and 1/6 of them are eating salads and 2/3 are eating sandwiches right? So you would have to think about what 1/6 of 18 is so you know how many students are eating salads, and 1/6 of 18 is 3 so there are 3 students eating salads. Now, you have to find out how many students are eating sandwiches, so you need to know what 2/3 of 18 is. 2/3 of 18 is 12 so now you also know that there are 12 students eating sandwiches. Next, you have to add 12 and 3 and you get 15. Since you know that there are 18 students in the cafeteria, you have to subtract 18 by 15, and you should get 3. So 3 students are eating lunches other than salads or sandwiches.
Hope this helps you! :D