Given:
Money they've already saved = $270
Trip will cost at least $500.
To find:
The amount they need to save more in order to make enough for the trip.
Solution:
Let they need $x more.
Money they've already saved = $270
Total money they will have = $(x+270)
Now, the trip will cost at least $500. It means, they need $500 or more than that. So, total money they will have needs to be greater than or equal to 500.
[tex]x+270\geq 500[/tex]
[tex]x\geq 500-270[/tex]
[tex]x\geq 230[/tex]
Therefore, they need $230 or more than that to make enough for the trip.
