00:01
All right, so let's write our total cost functions for each machine.
00:05
I have total cost for machine one, which is the purchase cost.
00:10
That's the fixed cost plus the variable cost, which is 10 ,000 times the number of units produced.
00:19
The total cost for machine two is going to be a hundred and twenty thousand plus nine.
00:28
Where did that 10 ,000 come from? that should be just ten.
00:34
Ten dollars times the number of units produced.
00:38
And then for machine two it was a hundred and twenty thousand, which is your fixed cost plus 9x.
00:47
For machine three you have a fixed cost of two hundred thousand and then a variable cost of 7 .5 times the number of units produced.
00:59
And for machine four you have a fixed cost of three hundred thousand and a variable cost of 5 .5 times the number of units produced.
01:13
And we want to know the ranges over which each machine would be least costly alternative.
01:23
Well, let's see how we would do this.
01:37
If tc1 is the least costly, then 8 ,000 plus 10x would be less than a hundred and twenty thousand plus 9x, which means that subtracting 9x from both sides i get x.
02:04
Subtracting 80 ,000 from both sides i get 40 ,000.
02:11
So this is for machine two.
02:17
And then 80 ,000 would also be less than the cost from machine three, so 200 ,000 plus 7 .5x.
02:31
So this was machine three.
02:34
And then subtracting 7 .5x from both sides and 80 ,000 from both sides so that then gives me x is less than 120 ,000 divided by 2 .5.
02:53
That is 48 ,000.
02:57
And it would have to be less than the cost of using machine four, so 300 ,000 plus 5 .5x.
03:12
And that means that 4 .5x has to be less than 220 ,000.
03:21
So x would have to be less than 4 .5.
03:51
Okay, so if x is less than 40 ,000 it is the least expensive because it satisfies all of those.
04:09
Then let's see here.
04:12
Tc2 is least expensive.
04:18
Or machine two...