Given:
selling price = $147
mark up = 75%
Asked:
original cost
The solution:
Selling price is the sum of the original cost and mark up price. It could be written as following,
Original cost + mark up price = selling price
100% original cost + 75% original = selling price
175% original cost = selling price
1.75 original cost = selling price
Solve for original cost
original cost = selling price/1.75
Plug in the numbers
original cost = selling price/1.75
original cost = 147/1.75
original cost = 84
The original cost of the skateboard is $84