In a closed room containing 40m3 of air and an electric fan to promote uniform mixing, how many kilograms of a typical combustible would have to burn to create an atmosphere that might incapacitate people in 30 minutes? Assuming harber's rule hold, how many burned kilograms of fuel might cause incapacitation in 10 minutes?

lol we need to see what the question is asking about

step-by-step explanation:

for this case we must apply distributive property to the following expression:

the distributive property states that:

then, when applying the property we have to multiply the -2 for each term within the parenthesis:

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.