The Downhill Ski club is organizing a ski trip. Group tickets for the ski trip are priced at $20 for the first 100 skiers and a discount of $5.00 per ticket for each of the skiers over 100.

a) write a formula to find the cost of x skiers.

Answer: c(x)=2000+15(x-100), if x>100

b) How many skiers need to go to bring the price per ticket to $16.00.

You got part (a) correct.

For (b), solve:

2000+15(x-100) = 16 x
x = 2000 -1500 = 500

400 of the 500 skiers get $15 tickets.
Total revenue is 6000 from them and 2000 from the first 100, or $8000. That is an average of $16 each.

To find the number of skiers needed to bring the price per ticket to $16.00, we can set up the equation:

$16.00 = $20.00 - ($5.00 * (x - 100))

Where x represents the number of skiers.

Simplifying the equation:
$16.00 = $20.00 - $5.00x + $500.00

Moving the terms around:
$5.00x = $500.00 - $20.00 + $16.00

$5.00x = $496.00

Dividing both sides by $5.00:
x = $496.00 / $5.00

x = 99.2

Since we cannot have a fraction of a skier, we can conclude that we will need at least 100 skiers to bring the price per ticket to $16.00.

To find the number of skiers needed to bring the price per ticket to $16.00, we can set up an equation using the formula from part (a).

Let's set up the equation:

c(x) = 2000 + 15(x - 100)

We want the cost per ticket to be $16.00, so we can replace "c(x)" with 16:

16 = 2000 + 15(x - 100)

Now, we can solve for x:

16 - 2000 = 15(x - 100)

-1984 = 15x - 1500

-1984 + 1500 = 15x

-484 = 15x

Dividing both sides by 15:

-484/15 = x

x ≈ -32.27

Since we can't have a negative number of skiers, we round up to the nearest whole number.

Therefore, approximately 33 skiers need to go to bring the price per ticket to $16.00.