Please answer the question below.

Table 117 Demand and cost data for a monopolist Price Quantity TR MR TC Profit $10 10 10 4 8 12 16 20 Il-screen Snip 24 28 32 36 10 40 Refer to Table 116 . The marginal revenue at a price of $5 is $ ___. (Enter the minus sign, if negative; no $ sign)