Well she filled up in Pasadena and filled up the gas cans. Her car had a 12-13 gallon capacity.
From Pasadena to Desert Center, it's 171 miles and takes 5 gallons of gas in a 2008 Ford Focus. On cross-exam, Jodi says she was running low on gas and filled up approx 12 gallons - that's not possible, but she could have topped off.
From Desert Center, CA to Buckeye, AZ, it's 170 miles and takes 5 gallons of gas. She said she filled up again in Buckeye and conceded on cross that she was running low on gas, so another 12 gallons of gas in Buckeye - this is not possible, and I do not believe she would have stopped at a gas station this close to Travis' home.
From Buckeye, AZ to Mesa, AZ is 56 miles and takes 1.7 gallons of gas.
If you assume Desert Center and Buckeye are fabrications because we don't have receipts and the appearance is Jodi is trying to be a ghost on her way to Travis' -- from Pasadena to Mesa is 386 miles and would take 11 gallons of gas. Jodi could make it to Mesa without stopping for gas, and have about 1 gallon to spare.
From Mesa to Hoover Dam is 293 miles and takes 8.6 gallons of gas.
From Hoover Dam to Mesquite, AZ it's 114.5 miles and takes 3.5 gallons of gas. In Mesquite, AZ she purchased $46.11 worth of gasoline --at least 10 gallons. There is no receipt for this gas purchase, and Jodi has not testified about getting gas here - we see this only on the bank statement that Juan entered yesterday.
So from Mesa to Mesquite, AZ, via Hoover Dam, Jodi would have used a little over 12 gallons at a minimum. That is a little more gas than she could have had left over in her tank plus 2, 5-gallon cans. Either she did stop between Mesa and Pasadena, or she had 3 gas cans. If she did stop for gas between Pasadena and Mesa, however, she would not have had to use the gas in the extra cans, so they would have remained full -- and she could not have filled them in SLC, which we know she did. Ergo, she had to have had 3 gas cans.
From Mesquite, AZ to West Jordan, UT, it's 331 miles, and takes 10 gallons of gas
From West Jordan to SLC, it's 13 miles and takes .5 gallons of gas.
In SLC she purchased 20.25 gallons of gas (not counting the possible purchase for the 3rd gas can). Presumably she filled up her car and the two cans, since this is way more gas than her car can hold.
From SLC to Winnemuca, NV, it's 354 miles and takes 10.4 gallons of gas. She said she was almost on empty when she filled up her car in Winnemuca. She purchased 12 gallons of gas.
From Winnemuca, NV to Sparks, NV it's 163 miles and takes 4.8 gallons of gas. In Sparks, she bought 5 gallons of gas. So she would have a full tank of gas and an extra 10 gallons in the trunk.
From Sparks, NV to Yreka, CA , it's 255 miles and takes 7.7 gallons of gas
From Yreka, CA to Redding, CA, it's 98 miles and takes 3 gallons of gas. In Redding she purchased 9.47 gallons of gas, presumably filling the tank.
At the end of her trip, she should have also still had 10 gallons of gas in the extra cans if she did not go anywhere else.
CONCLUSION:
1. She could not have made it from Pasadena to Mesquite on a tank of gas and 2, 5-gallon cans.
2. She could make it to Mesquite, NV if she had three extra 5-gallon cans OR if she filled up in Buckeye.
3. If she got filled up in Buckeye, then she would not have needed to use the extra gas cans at any time before she filled up again in Mesquite. And after filling up in Mesquite, she had enough gas to get her to West Jordan and then to SLC, and she still would not have needed the extra cans. But in SLC she filled up the extra 5-gallon cans, so she had to have used them. That means she did not fill up in Buckeye.
4. Since she didn't fill up in Buckeye, she must have used the extra tanks -- but since she couldn't make it all the way to Mesquite with 2 extra cans, she had to have had 3 extra gas cans.
5. Unless she went somewhere else after Sparks, NV, she should have ended her trip with 2 full 5-gallon gas cans.