Adjusting chart Y-axis value using VBA

Hi All,

I have a chart whose minimum value I would like to adjust based on the minimum value in a named range. So for eg if my named range is called Average_weight and if the minimum value of this named range is 40 then I would like the chart's Y-axis to have a minimum value of 40.

How could I achieve this? Also I would like it to be done such that the minimum value is a rounded down figure i.e. if the minimum value of the named range comes to be 38.76 the minimum value of the Y-axis should be 30. If the minimum value comes to be 22.3 the minimum value of the Y-axis should be 20. This would let me maintain intervals of 10 on my Y-axis.

Many Thanks