An Apple ipod sells for $299, which is marked up 40% of the selling price. The cost of the Ipod is what?

This means that the original price is 60%, which we will use to calculate it.

299 (the discounted price) : x (the original price) = 60 % : 100 %

60x = 299 * 100

60x = 29900

x = 29900 / 60

x = 498.33

The cost of the Ipod is $498.33