Which table represents a exponential decay?

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.

You deposit $5000 each year into an account earning 3% interest compounded annually. how much will you have in the account in 30 years?

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way