Show Qty and Value in line chart

[johngouws]

Hi All. 

I want to show Sales and GP and Qty in a line chart. Because the Qty values are so small compared to the money values, the line for Qty is hardly visible. How can one overcome this? 

The expressions are simply Sum(Sales) & Sum(GP) & Sum(Qty). Below is what my chart looks like. 

I wonder how to overcome this? 

Thank you.