Answer :
Answer: 2.25 cups of hot tap water and 0.75 cup of refrigerated water.
Step-by-step explanation:
Let x= Number of cups of hot tap water that is 140°F.
and y = Number of cups of refrigerated water that is 40°F.
To find : How much each of them we should mix to get 3 cups of 115° F water.
According to the question , we have
[tex]x+y= 3\Rightarrow\ y= 3-x\ \ \ ...(i)\\\\\ 140x+40y=115(3)\Rightarrow\ 140x+40y=345\ \ ...(ii)[/tex]
Substitute value of y from (i) in (ii) , we get
[tex]140x+40(3-x)=345\\\\\Rightarrow\ 140x+120-40x=345\\\\\Rightarrow\ 100x=345-120\\\\\Rightarrow\ 100x=225\\\\\Rightarrow\ x=\dfrac{225}{100}\\\\\Rightarrow\ x= 2.25[/tex]
Put this in (i) , y= 3-2.25=0.75
Hence, we require 2.25 cups of hot tap water and 0.75 cup of refrigerated water.
The amount of hot and cold water should be 2.25 cups & 0.75 cups respectively.
Find the Average temperature
Average temperature: (desired) with hot and cold water = 115
Important Assumption
Let the proportion of hot and cold water be x and y cups respectively. So, Total cups = 3
So, [tex]x + y = 3 ...(i)[/tex]
The average temperature is found by the concentration of warm and cold water temperature:
[tex](40x + 40y) / 3 = 115 ...(ii)[/tex]
[tex]40x + 40y = 345[/tex]
From eq i), [tex]y = 3 - x[/tex]
Putting the value in eq ii),
[tex]140x + 40 (3 -x) = 345\\140x + 120 - 40x = 345 \\100x = 225 x = 2.25[/tex]
Putting the value of x in equation i), [tex]y = 3 - 2.25 = 0.75[/tex]
To learn more about average temperature, refer https://brainly.com/question/8779347?referrer=searchResults
