I don't understand this ​

Step-by-step explanation:

n=1/2 of 12 according to the rule:

right triangle the side opposite the 30 degree angle is half the length of the hypotenuse.

so n=12/2=6

and now we will need Pythagorean theorem : the sum of the squares on the legs of a right triangle is equal to the square on the hypotenuse (the side opposite the right angle)—or, in familiar algebraic notation, a2 + b2 = c2.

so

now lets put numbers on formula

from this formula m=

the workers who do no drive has no reasonable reason to buy gasoline due to they don't have anything to use it for

b is the right answer