Answer:
1 quart must be added
Explanation:
To do this, set up an equation.
Let x be the number of quarts of antifreeze to be added. Then, you know that the new solution will have a total of 4 quarts with 2/5 of it being antifreeze, so
would be the amount of antifreeze. Another way to represent the amount of antifreeze is
because the original mixture has 3/5 of quart of antifreeze, while the added stuff is fully antifreeze.
Now, you just solve the equation:
![(2)/(5) (x + 3) = x + (3)/(5)](https://img.qammunity.org/2022/formulas/mathematics/college/jq53yz8m0pbqje1gxw5pe8fcpe5bpqfjvo.png)
multiply both sides by 5
![2(x + 3) = 5x + 3](https://img.qammunity.org/2022/formulas/mathematics/college/dc312nkt5o771iwroh7u74ya8gcbbpxrqk.png)
Use the distributive property on the left
![2x + 6 = 5x + 3](https://img.qammunity.org/2022/formulas/mathematics/college/ldrm7r72d59zoh9n9klz3zrbtyvg77p3jy.png)
subtract 2x from both sides
![6 = 3x + 3](https://img.qammunity.org/2022/formulas/mathematics/college/5keojausl66jh7wuk2fouswhsth5k13dk1.png)
subtract 3 from both sides
![3 = 3x](https://img.qammunity.org/2022/formulas/mathematics/college/b7n8yvzfncqxmveugxo43zo15qbdfxt51c.png)
divide both sides by 3
![1 = x \\x = 1](https://img.qammunity.org/2022/formulas/mathematics/college/5xq0c0u87i1kyjcrtsdp00o4qy4lbjemxx.png)
Therefore the answer is 1 quart