Let x be the number of electronic digital timers manufactured or sold in a month.

(a) To set up the cost function, we need to consider the variable cost and the fixed cost.

The variable cost is the production cost, which is $7 for each timer. So the production cost of making x number of timers is 7x.

The fixed cost is the amount $46000 per month.

So the total cost of manufacturing x number of timers in a month is:

`C(x) = 7x + 46000`

(b) The formula for revenue is:

Revenue = Price per unit * quantity sold

The selling price of each timer is $14. So, our revenue function in selling x number of digital timers in a month is:

`R(x) = 14x`

(c) To get the profit in selling x number of digital timers, we have to subtract the total cost from the revenue.

`P(x) = R(x) - C(x)`

Plugging in our revenue function and cost function, this formula becomes:

`P(x) = 14x - (7x + 46000)`

This simplifies to:

`P(x) = 7x - 46000`

This is the profit function in selling x number of digital timers in a month.

(d) The profit/loss when 3000 digital timers is produced and sold is:

`P(3000) = 7(3000) - 46000 = -25000`

Thus, when 3000 timers are produced and sold, there is a loss of $25000.

The profit/loss when 5000 digital timers are produced and sold is:

`P(5000)=7(5000)-46000= -11000`

There is a loss of $11000 when 5000 digital timers are produced and sold.

The profit/loss in producing and selling 13000 digital timers is:

`P(13000)=7(13000)-46000=45000`

Therefore, when 13000 digital timers are produced and sold, there is a profit of $45000.