Please I need both answers I'm stuck.

4. It will cost $2,200 to acquire an ice cream cart. Cart sales are expected to be $1,500 a year for three years. After the three years, the cart is expected to be worthless as the expected life of the refrigeration unit is only three years. What is the payback period?

3. What is the profitability index for an investment with the following cash flows given a 9 percent required return?

Year	Cash Flow
0	$-21,500
1	$7,300
2	$9,700
3	$8,700