Question

A compact car will drive three miles east, five miles west, and then 13 miles east again. The car
gets 40 miles per gallon, and there is
1
4 of a gallon of gas left in the tank. Compute the relative
distance and the total distance. Then decide if there is enough fuel for the trip.

Answer 1

Is that 1/4? @xXxMissyxXx

Answer 2

yes

Answer 3

yes it is 1/4 @genius12

Answer 4

@xXxMissyxXx The total distance travelled is simply the sum of all the distances, i.e:

Total distance = 3 miles + 5 miles + 13 miles = 21 miles

Now the relative distance refers to distance travelled relative to the starting point. You can pretty much think of it as displacement. Here, the directions and the distance travelled from starting point are:

3 miles east
5 miles west
13 miles east

It is clear that the relative distance then is 3 - 5 + 13 = 11 miles. This is because when you travel 3 miles east from your starting point, your relative distance is 3 miles. But when you travel 5 miles west, you are now 2 miles west from your starting point. And travelling 13 miles east again puts you 11 miles east of the starting point.

Lastly, we are given that the fuel economy is 40 miles/gallon. We calculated the total distance to be 21 miles and we have 1/4 gallons left. If we travel 40 miles for every gallon, then we travel 10 miles for 1/4 of a gallon. Since the distance is 21 miles, then there is not enough fuel to last the journey. @xXxMissyxXx

Answer 5

A good example of a similar question is here:
http://answers.yahoo.com/question/index?qid=20130116075523AAJKkoA
@xXxMissyxXx

Answer 6

@genius12 Thank you so much I was trying to figure out how to calculate the relative distance but I wasn't understanding it correctly! :)

Answer 7

@xXxMissyxXx fan me? =[ lol