Question

The Johnson family drove to the mountains for a vacation. Mr.Johnson drove x miles. Mrs. Johnson drove 2 times the number of miles that Mr. Johnson did. If the Johnsons drove 330 miles, how many miles did Mrs. Johnson drive?

Answer 1

220 miles is how much Mrs. Johnson drove. because . . .

2x+x=330
2x is twice the amount of Mr. Johnson which equals Mrs. Johnson.
The plain "x" is how much Mr. Johnson drove. 

2x+x= 3x
3x=330- x=110

If 'x' is how much Mr. Johnson drove then we multiply that by two to get 220.