I cannot wrap my head around the formula to use for a dollar cost average calculation. Normal calculations are Average price per share = total sum invested / total shares in the scenario I'm looking at someone has bought for 150$ shares against the rate of 2$ each. The current rate per share is 0.37$ and he wants to bring down his average price per share down to 0.4$ The way I was writing out the formula was: 0.4 = (150+x)/( 300+y) First of all is this a correct understanding and secondly how to find values for X and Y?