In 20 l of air, there is about 0.78 l of carbon dioxide. about how many liters of carbon dioxide are there in 1 l of air?

So for this we will be setting up a proportion. Since we know that for 20 L of air there is 0.78 L of CO₂, we can determine that for 1 L of air there is X L of CO₂ . We can set that up as such:

From here we can solve for x. Firstly, cross-multiply:

Next, divide both sides by 20:

For 1 L of air, there is 0.039 L of CO₂

3< x< 5

step-by-step explanation:

|x - 4| < 1

there are two solutions, one positive and one negative.   remember to flip the inequality when taking the negative solution

x-4 < 1       x-4 > -1

add 4 to each side

x-4+4 < 1+4       x-4+4 > -1+4

x< 5                 x> 3

3< x< 5

answer:     true

step-by-step explanation: