I need help with learning systems of equations

You work for a lender that requires a 20% down payment and uses the standard depth to income ratio to determine a person‘s a little eligibility for a home loan of the following choose the person that you would rate the highest on their eligibility for a home loan

An appliance store sells a washer-dryer combination for $1800. if the washer costs $300 more than the dryer, find the cost for each appliance.

Issof claims that the scale factor is 1/2. which statement about his claim is correct