A souvenir store charges PHP 15.00 per keychain for the first 50 orders. If the order exceeds to 50 keychains, the store charges PHP 12.50 per keychains for the exceeded orders of keychains. Express the total cost K(x) of the x number of keychains as a function of x.

Answer 1

For the first 50 keychains, the cost is PHP 15.00 per keychain. So, the cost for the first 50 keychains is 15*x, where x is the number of keychains.

If the order exceeds 50 keychains, the store charges PHP 12.50 per keychain for the exceeded orders. So, the cost for the exceeded orders is 12.50*(x-50).

Thus, the total cost K(x) of the x number of keychains is given by:

K(x) = 15*x + 12.50*(x-50)

Simplifying further:

K(x) = 15x + 12.50x - 12.50*50

K(x) = 27.50x - 625