Question

Mary sells fax machines which come in Standard and Enhanced models. The Standard model sells for $230 and the Enhanced model sells for $305. If Mary sold a total of 31 units and took in $7,730, how many of the Enhanced model did she sell?
Do not enter units.

Answer 1

If she sells x of the $305 models, then the rest (31-x) are $230. So, now just add up the values.

305x + 230(31-x) = 7730

and find x