In part (c) the firm increased price. Shoe sales fell, but by
a smaller percentage than the price rose so revenue increased.
In this case, since the firm is selling fewer shoes its costs
must have fallen too. Thus, since its revenue rose and its costs
fell we can say that its profits increased. This is why we can
say that any profit maximizing firm facing inelastic demand would
increase price if it did not have to worry about competitors.