we know that
The Rodriguez family has a fixed income of $4,000 a month.
Their fixed expenses are $1,800 a month
so
The remaining amount in a month is
4,000-1,800=$2,200
The one fourth of the remaining income is
(1/4)(2,200)=$550
To find out the minimum amount in a year, multiply $550 by 12
550*(12)=$6,600
therefore
the answer is
$6,600