I hope you can understand me, but $57 for 80m of water. So you divide 57 by 80. That equals 0.7125. Now you have the unit price of one m of water. Since you’re looking for the price of 50m of water, you multiply 0.7125 by 50, which equals 35.625. Since you’re talking about dollars, you need to round to the nearest hundredth. Therefore, the price for 50m of water is $35.63. I hope this helps.