Which of the following is true for calculating the future value of multiple cash flows? a) You can only find the FV of multiple cash flows if the payments occur with the same regularity. b) To find the FV of multiple cash flows, add the PV of each cash flow together and use the total in the formula for FV. c) It is simpler to find the FV of irregular cash flows than of annuities. d) You must choose the same point in the future for each individual cash flow to determine the FV of multiple investments.

The monthly demand equation for an electric utility company is estimated to be p equals 60 minus left parenthesis 10 superscript negative 5 baseline right parenthesis x, where p is measured in dollars and x is measured in thousands of killowatt-hours. the utility has fixed costs of $3 comma 000 comma 000 per month and variable costs of $32 per 1000 kilowatt-hours of electricity generated, so the cost function is upper c left parenthesis x right parenthesis equals 3 times 10 superscript 6 baseline plus 32 x. (a) find the value of x and the corresponding price for 1000 kilowatt-hours that maximize the utility's profit. (b) suppose that the rising fuel costs increase the utility's variable costs from $32 to $38, so its new cost function is upper c 1 left parenthesis x right parenthesis equals 3 times 10 superscript 6 baseline plus 38 x. should the utility pass all this increase of $6 per thousand kilowatt-hours on to the consumers?