I have a solar hot water collector that puts out water at a very scalding 160 f . directly into the house hot water line ; My ideal water temperature for a shower is 95 f . If i mix in cooler water from my showers cold water faucet which delivers 75 f. during summer months , what percentage of Collector water (160 f) do I need to achieve a 95 f. shower ? If you would, please give me the mathematical formula by plugging in the values listed for the answer. I do appreciate it. Thanks, David.