Surface Company sells square wooden blocks. A typical batch of 100 blocks has rough sides and costs $100 to produce. These rough blocks sell for $10 each.

Surface Company can spend an additional $10 to sand down the sides of the blocks so that they are smooth and sell each smooth block for $15.

What is the change to Surface Company's cash flow for a batch of blocks that it decides to process further into smooth blocks?

Show a cash inflow as a positive number and a cash outflow as a negative number.