Step-by-step explanation
Step 1
let x represents the numbers of days you can stay at the beach
then,
You estimate that it will cost $160 a day for food, entertainment and hotel, plus $230 round trip airfare.
so
but, you have only $1200, so the total needs to be smaller or equal than 1200
Step 2
solve the inequality
it means you can stay maximum 6 days
I hope this helps you