# The cost of buying computer chips is $2/piece for the first 100 and $1.75/piece beyond that. Write an expression for the cost of p chips and draw a graph of the function.

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The cost of the first 100 computer chips is $2/piece and the chips bought after that are for $1.75 each.

For p chips the cost function is

`C(p) = 2*p` for `p<= 100 `

`C(p) =` `200 + (p - 100)*1.75` for `p > 100` .

The graph of the function is:

It can be seen that the slope of the graph is 2 initially and reduces to 1.75 after 100.

Let Y is the total cost in $ and X be the number of chips you buy.

Then for your first 100 chips;

**Y= 2*X (X<=100)**------------(1)

For chips more than 100 you will definitely pay 200$ for first 100. The rest you will pay 1.75$ each. So the equation valids only when X is beyond 100.

**Y = 200+(x-100)*1.75 ; (X>100)**-------(2)

OR

**Y = 100*2+(x-100)*1.75 ; (X>100)**-----(2)

**When plotting the graphs (1) plots only from X=0 to X=100**

**This is a simple y=mx type graph. This graph start through cordinate(0,0) and ends at (100,200)**

**If you connect these two points you will get the graph.**

**When plotting grapgh (2) it plots when X>100**

**It is a y=mx+c type graph. This graph start through cordinate (101,201.75) and end cannot be set. But the graph will pass the point (110,217.5)**

**From (101,201.75) you can draw a line which also goes through (110,217.5) which will give you the graph.**