Mary uses one third of a gallon of gasoline driving back and forth to work every day. How much gasoline does she use in 30 days?

10 gallons

Step-by-step explanation:

1/3 x 30/1 =  30/3  =10

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x