Explanation
We are told that the amount Justin saves is given by:
[tex]A=145N+750[/tex]And the amount saved by his wife is given by:
[tex]B=485N[/tex]The total amount saved by the two will be:
[tex]A+B=145N+750+485N[/tex]simplifying further
[tex]A+B=750+630N[/tex]Therefore, the total amount saved by the couple will be
[tex]A+B=750+630N[/tex]