Need help with formula for expect income!

Sound City sells the TrueSound-XL radio. Based off the past 100 weeks of sales data, the managers find that there were 3 weeks in which no radios sold, 20 weeks with one radio sold, 50 weeks with two radios sold, 20 weeks with three radios sold, 5 weeks with four radios sold, and 2 weeks with 5 radios sold