Question

Meg started her trip with 11 1/2 gallons of gas in her car's tank. She bought an additional 6 4/5 gallons on her trip and arrived back home with 3 3/10 gallons left. How much gas did she use on the trip?

Answer 1

Meg used 15 gallons. First you find the  lowest common denominator to add 11 1/2 and 6 4/5, which is 10. What you do to the bottom you have to do to the top. You multiply 2 and 5, which gives you 10. 1 times 5 is 5... 11 5/10. 2 times 5 is 10, 4 times 2 is 8... 6 8/10. Add 11 5/10 and 6 8/10 and it gives you 18 3/10. To find out how much she used subtract the total amount she bought and how much she returned home with. The fractions cancel out since 3/10 minus 3/10 equals 0. You're just left with 18 minus 3, which is 15.

Answer 2

Hence, the amount of gas she used on the trip is:

15 gallons.

Explanation:

Meg started her trip with 11 1/2 gallons of gas in her car's tank.

i.e. we can represent the mixed fraction 11 1/2 in fraction as:

`11(1)/(2)=(23)/(2)gallons`

She bought an additional 6 4/5 gallons on her trip.

i.e. we can represent the mixed fraction 6 4/5 in fraction as:

`6(4)/(5)=(34)/(5)gallons`

Hence, the amount of gas filled in tank:

`=(23)/(2)+(34)/(5)\\\\=(23* 5+34* 2)/(10)\\\\=(115+68)/(10)\\\\=(183)/(10)gallons`

now after coming back home the amount of gas left in the car tank is:

3 3/10 gallons ; which could be represented in fraction as:

`3(3)/(10)=(33)/(10)`

Amount of gas used in the trip is:

=Amount of gas filled-gas remaining

`=(183)/(10)-(33)/(10)\\\\=(183-33)/(10)\\\\=(150)/(10)\\\\=15gallons`

Hence, the amount of gas she used on the trip is:

15 gallons.