Hey you guys! Can anyone help me with this problem? I’m absolutely stumped and I’ve been trying to solve it all night.

I have a 500mg/ml concentration that is made with 10g of solute and 12.5ml of solvent in 20mL

What does my solvent and solute need to be to have a 600 and 700 mg/ml concentration, respectively at the same 20mL volume amount