Calculate the payback periods on the following investments and determine the least risky investment as measured by lowest payback period. See following:

• New product 1 investment = $60 million
• New product 1 cash inflows = $12 million
• New product 1 cash outflows = $4 million
• New product 2 investment = $25 million
• New product 2 cash inflows = $8 million
• New product 2 cash outflows = $2 million
• New product 3 investment = $35 million
• New product 3 cash inflows = $15 million
• New product 3 cash outflows = $5 million
• New product 4 investment = $20 million
• New product 4 cash inflows = $6 million
• New product 4 cash outflows = $2 million