Answer:
20 gallons
Step-by-step explanation:
To solve, we can use a proportion
She used 12 gallons for 294 miles, and x gallons for 490 miles
12/294=x/490
Cross multiply
294*x=12*490
294x=5880
We want to solve for x. To do that, we need to get x by itself. Since x is being multiplied by 294, divide both sides by 294.
294x/294=5880/294
x=20
So, she needs 20 gallons to drive 490 miles